blob: a237ba632e8d93dea4d7d4b42fcef196d081f011 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/locks.c
3 *
4 * Provide support for fcntl()'s F_GETLK, F_SETLK, and F_SETLKW calls.
5 * Doug Evans (dje@spiff.uucp), August 07, 1992
6 *
7 * Deadlock detection added.
8 * FIXME: one thing isn't handled yet:
9 * - mandatory locks (requires lots of changes elsewhere)
10 * Kelly Carmichael (kelly@[142.24.8.65]), September 17, 1994.
11 *
12 * Miscellaneous edits, and a total rewrite of posix_lock_file() code.
13 * Kai Petzke (wpp@marie.physik.tu-berlin.de), 1994
14 *
15 * Converted file_lock_table to a linked list from an array, which eliminates
16 * the limits on how many active file locks are open.
17 * Chad Page (pageone@netcom.com), November 27, 1994
18 *
19 * Removed dependency on file descriptors. dup()'ed file descriptors now
20 * get the same locks as the original file descriptors, and a close() on
21 * any file descriptor removes ALL the locks on the file for the current
22 * process. Since locks still depend on the process id, locks are inherited
23 * after an exec() but not after a fork(). This agrees with POSIX, and both
24 * BSD and SVR4 practice.
25 * Andy Walker (andy@lysaker.kvaerner.no), February 14, 1995
26 *
27 * Scrapped free list which is redundant now that we allocate locks
28 * dynamically with kmalloc()/kfree().
29 * Andy Walker (andy@lysaker.kvaerner.no), February 21, 1995
30 *
31 * Implemented two lock personalities - FL_FLOCK and FL_POSIX.
32 *
33 * FL_POSIX locks are created with calls to fcntl() and lockf() through the
34 * fcntl() system call. They have the semantics described above.
35 *
36 * FL_FLOCK locks are created with calls to flock(), through the flock()
37 * system call, which is new. Old C libraries implement flock() via fcntl()
38 * and will continue to use the old, broken implementation.
39 *
40 * FL_FLOCK locks follow the 4.4 BSD flock() semantics. They are associated
41 * with a file pointer (filp). As a result they can be shared by a parent
42 * process and its children after a fork(). They are removed when the last
43 * file descriptor referring to the file pointer is closed (unless explicitly
44 * unlocked).
45 *
46 * FL_FLOCK locks never deadlock, an existing lock is always removed before
47 * upgrading from shared to exclusive (or vice versa). When this happens
48 * any processes blocked by the current lock are woken up and allowed to
49 * run before the new lock is applied.
50 * Andy Walker (andy@lysaker.kvaerner.no), June 09, 1995
51 *
52 * Removed some race conditions in flock_lock_file(), marked other possible
53 * races. Just grep for FIXME to see them.
54 * Dmitry Gorodchanin (pgmdsg@ibi.com), February 09, 1996.
55 *
56 * Addressed Dmitry's concerns. Deadlock checking no longer recursive.
57 * Lock allocation changed to GFP_ATOMIC as we can't afford to sleep
58 * once we've checked for blocking and deadlocking.
59 * Andy Walker (andy@lysaker.kvaerner.no), April 03, 1996.
60 *
61 * Initial implementation of mandatory locks. SunOS turned out to be
62 * a rotten model, so I implemented the "obvious" semantics.
Paul Bolle395cf962011-08-15 02:02:26 +020063 * See 'Documentation/filesystems/mandatory-locking.txt' for details.
Linus Torvalds1da177e2005-04-16 15:20:36 -070064 * Andy Walker (andy@lysaker.kvaerner.no), April 06, 1996.
65 *
66 * Don't allow mandatory locks on mmap()'ed files. Added simple functions to
67 * check if a file has mandatory locks, used by mmap(), open() and creat() to
68 * see if system call should be rejected. Ref. HP-UX/SunOS/Solaris Reference
69 * Manual, Section 2.
70 * Andy Walker (andy@lysaker.kvaerner.no), April 09, 1996.
71 *
72 * Tidied up block list handling. Added '/proc/locks' interface.
73 * Andy Walker (andy@lysaker.kvaerner.no), April 24, 1996.
74 *
75 * Fixed deadlock condition for pathological code that mixes calls to
76 * flock() and fcntl().
77 * Andy Walker (andy@lysaker.kvaerner.no), April 29, 1996.
78 *
79 * Allow only one type of locking scheme (FL_POSIX or FL_FLOCK) to be in use
80 * for a given file at a time. Changed the CONFIG_LOCK_MANDATORY scheme to
81 * guarantee sensible behaviour in the case where file system modules might
82 * be compiled with different options than the kernel itself.
83 * Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
84 *
85 * Added a couple of missing wake_up() calls. Thanks to Thomas Meckel
86 * (Thomas.Meckel@mni.fh-giessen.de) for spotting this.
87 * Andy Walker (andy@lysaker.kvaerner.no), May 15, 1996.
88 *
89 * Changed FL_POSIX locks to use the block list in the same way as FL_FLOCK
90 * locks. Changed process synchronisation to avoid dereferencing locks that
91 * have already been freed.
92 * Andy Walker (andy@lysaker.kvaerner.no), Sep 21, 1996.
93 *
94 * Made the block list a circular list to minimise searching in the list.
95 * Andy Walker (andy@lysaker.kvaerner.no), Sep 25, 1996.
96 *
97 * Made mandatory locking a mount option. Default is not to allow mandatory
98 * locking.
99 * Andy Walker (andy@lysaker.kvaerner.no), Oct 04, 1996.
100 *
101 * Some adaptations for NFS support.
102 * Olaf Kirch (okir@monad.swb.de), Dec 1996,
103 *
104 * Fixed /proc/locks interface so that we can't overrun the buffer we are handed.
105 * Andy Walker (andy@lysaker.kvaerner.no), May 12, 1997.
106 *
107 * Use slab allocator instead of kmalloc/kfree.
108 * Use generic list implementation from <linux/list.h>.
109 * Sped up posix_locks_deadlock by only considering blocked locks.
110 * Matthew Wilcox <willy@debian.org>, March, 2000.
111 *
112 * Leases and LOCK_MAND
113 * Matthew Wilcox <willy@debian.org>, June, 2000.
114 * Stephen Rothwell <sfr@canb.auug.org.au>, June, 2000.
115 */
116
117#include <linux/capability.h>
118#include <linux/file.h>
Al Viro9f3acc32008-04-24 07:44:08 -0400119#include <linux/fdtable.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120#include <linux/fs.h>
121#include <linux/init.h>
122#include <linux/module.h>
123#include <linux/security.h>
124#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125#include <linux/syscalls.h>
126#include <linux/time.h>
Dipankar Sarma4fb3a532005-09-16 19:28:13 -0700127#include <linux/rcupdate.h>
Vitaliy Gusevab1f1612008-01-17 00:07:08 +0000128#include <linux/pid_namespace.h>
Jeff Layton48f74182013-06-21 08:58:18 -0400129#include <linux/hashtable.h>
Jeff Layton7012b022013-06-21 08:58:22 -0400130#include <linux/percpu.h>
131#include <linux/lglock.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132
Jeff Layton62af4f12014-05-09 14:13:05 -0400133#define CREATE_TRACE_POINTS
134#include <trace/events/filelock.h>
135
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136#include <asm/uaccess.h>
137
138#define IS_POSIX(fl) (fl->fl_flags & FL_POSIX)
139#define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK)
J. Bruce Fields617588d2011-07-01 15:18:34 -0400140#define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG))
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400141#define IS_OFDLCK(fl) (fl->fl_flags & FL_OFDLCK)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -0400143static bool lease_breaking(struct file_lock *fl)
144{
J. Bruce Fields778fc542011-07-26 18:25:49 -0400145 return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING);
146}
147
148static int target_leasetype(struct file_lock *fl)
149{
150 if (fl->fl_flags & FL_UNLOCK_PENDING)
151 return F_UNLCK;
152 if (fl->fl_flags & FL_DOWNGRADE_PENDING)
153 return F_RDLCK;
154 return fl->fl_type;
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -0400155}
156
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157int leases_enable = 1;
158int lease_break_time = 45;
159
160#define for_each_lock(inode, lockp) \
161 for (lockp = &inode->i_flock; *lockp != NULL; lockp = &(*lockp)->fl_next)
162
Jeff Layton1c8c6012013-06-21 08:58:15 -0400163/*
Jeff Layton7012b022013-06-21 08:58:22 -0400164 * The global file_lock_list is only used for displaying /proc/locks, so we
165 * keep a list on each CPU, with each list protected by its own spinlock via
166 * the file_lock_lglock. Note that alterations to the list also require that
167 * the relevant i_lock is held.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400168 */
Jeff Layton7012b022013-06-21 08:58:22 -0400169DEFINE_STATIC_LGLOCK(file_lock_lglock);
170static DEFINE_PER_CPU(struct hlist_head, file_lock_list);
Jeff Layton88974692013-06-21 08:58:14 -0400171
Jeff Layton1c8c6012013-06-21 08:58:15 -0400172/*
Jeff Layton48f74182013-06-21 08:58:18 -0400173 * The blocked_hash is used to find POSIX lock loops for deadlock detection.
Jeff Layton7b2296a2013-06-21 08:58:20 -0400174 * It is protected by blocked_lock_lock.
Jeff Layton48f74182013-06-21 08:58:18 -0400175 *
176 * We hash locks by lockowner in order to optimize searching for the lock a
177 * particular lockowner is waiting on.
178 *
179 * FIXME: make this value scale via some heuristic? We generally will want more
180 * buckets when we have more lockowners holding locks, but that's a little
181 * difficult to determine without knowing what the workload will look like.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400182 */
Jeff Layton48f74182013-06-21 08:58:18 -0400183#define BLOCKED_HASH_BITS 7
184static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS);
Jeff Layton88974692013-06-21 08:58:14 -0400185
Jeff Layton1c8c6012013-06-21 08:58:15 -0400186/*
Jeff Layton7b2296a2013-06-21 08:58:20 -0400187 * This lock protects the blocked_hash. Generally, if you're accessing it, you
188 * want to be holding this lock.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400189 *
190 * In addition, it also protects the fl->fl_block list, and the fl->fl_next
191 * pointer for file_lock structures that are acting as lock requests (in
192 * contrast to those that are acting as records of acquired locks).
193 *
194 * Note that when we acquire this lock in order to change the above fields,
195 * we often hold the i_lock as well. In certain cases, when reading the fields
196 * protected by this lock, we can skip acquiring it iff we already hold the
197 * i_lock.
198 *
199 * In particular, adding an entry to the fl_block list requires that you hold
200 * both the i_lock and the blocked_lock_lock (acquired in that order). Deleting
201 * an entry from the list however only requires the file_lock_lock.
202 */
Jeff Layton7b2296a2013-06-21 08:58:20 -0400203static DEFINE_SPINLOCK(blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204
Christoph Lametere18b8902006-12-06 20:33:20 -0800205static struct kmem_cache *filelock_cache __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206
Miklos Szerediee19cc42011-07-07 13:06:09 +0200207static void locks_init_lock_heads(struct file_lock *fl)
Miklos Szeredia51cb912011-07-06 12:33:55 +0200208{
Jeff Layton139ca042013-06-21 08:58:17 -0400209 INIT_HLIST_NODE(&fl->fl_link);
Miklos Szerediee19cc42011-07-07 13:06:09 +0200210 INIT_LIST_HEAD(&fl->fl_block);
211 init_waitqueue_head(&fl->fl_wait);
Miklos Szeredia51cb912011-07-06 12:33:55 +0200212}
213
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214/* Allocate an empty lock structure. */
Arnd Bergmannc5b1f0d2010-10-27 15:46:08 +0200215struct file_lock *locks_alloc_lock(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216{
Miklos Szerediee19cc42011-07-07 13:06:09 +0200217 struct file_lock *fl = kmem_cache_zalloc(filelock_cache, GFP_KERNEL);
Miklos Szeredia51cb912011-07-06 12:33:55 +0200218
219 if (fl)
Miklos Szerediee19cc42011-07-07 13:06:09 +0200220 locks_init_lock_heads(fl);
Miklos Szeredia51cb912011-07-06 12:33:55 +0200221
222 return fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223}
Arnd Bergmannc5b1f0d2010-10-27 15:46:08 +0200224EXPORT_SYMBOL_GPL(locks_alloc_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225
Felix Blyakhera9e61e22009-03-31 15:12:56 -0500226void locks_release_private(struct file_lock *fl)
Trond Myklebust47831f32006-03-20 13:44:05 -0500227{
228 if (fl->fl_ops) {
229 if (fl->fl_ops->fl_release_private)
230 fl->fl_ops->fl_release_private(fl);
231 fl->fl_ops = NULL;
232 }
Trond Myklebust47831f32006-03-20 13:44:05 -0500233
Kinglong Mee5c97d7b2014-08-22 10:18:43 -0400234 if (fl->fl_lmops) {
235 if (fl->fl_lmops->lm_put_owner)
236 fl->fl_lmops->lm_put_owner(fl);
237 fl->fl_lmops = NULL;
238 }
Trond Myklebust47831f32006-03-20 13:44:05 -0500239}
Felix Blyakhera9e61e22009-03-31 15:12:56 -0500240EXPORT_SYMBOL_GPL(locks_release_private);
Trond Myklebust47831f32006-03-20 13:44:05 -0500241
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242/* Free a lock which is not in use. */
J. Bruce Fields05fa3132010-10-30 17:31:15 -0400243void locks_free_lock(struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244{
Miklos Szeredi5ce29642006-03-31 02:30:29 -0800245 BUG_ON(waitqueue_active(&fl->fl_wait));
246 BUG_ON(!list_empty(&fl->fl_block));
Jeff Layton139ca042013-06-21 08:58:17 -0400247 BUG_ON(!hlist_unhashed(&fl->fl_link));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248
Trond Myklebust47831f32006-03-20 13:44:05 -0500249 locks_release_private(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250 kmem_cache_free(filelock_cache, fl);
251}
J. Bruce Fields05fa3132010-10-30 17:31:15 -0400252EXPORT_SYMBOL(locks_free_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253
Jeff Laytoned9814d2014-08-11 14:20:31 -0400254static void
255locks_dispose_list(struct list_head *dispose)
256{
257 struct file_lock *fl;
258
259 while (!list_empty(dispose)) {
260 fl = list_first_entry(dispose, struct file_lock, fl_block);
261 list_del_init(&fl->fl_block);
262 locks_free_lock(fl);
263 }
264}
265
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266void locks_init_lock(struct file_lock *fl)
267{
Miklos Szerediee19cc42011-07-07 13:06:09 +0200268 memset(fl, 0, sizeof(struct file_lock));
269 locks_init_lock_heads(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270}
271
272EXPORT_SYMBOL(locks_init_lock);
273
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274/*
275 * Initialize a new lock from an existing file_lock structure.
276 */
Kinglong Mee3fe0fff12014-08-22 10:18:42 -0400277void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278{
279 new->fl_owner = fl->fl_owner;
280 new->fl_pid = fl->fl_pid;
Trond Myklebust09969052006-03-20 13:44:38 -0500281 new->fl_file = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282 new->fl_flags = fl->fl_flags;
283 new->fl_type = fl->fl_type;
284 new->fl_start = fl->fl_start;
285 new->fl_end = fl->fl_end;
Kinglong Meef3282962014-08-22 10:18:43 -0400286 new->fl_lmops = fl->fl_lmops;
Trond Myklebust09969052006-03-20 13:44:38 -0500287 new->fl_ops = NULL;
Kinglong Meef3282962014-08-22 10:18:43 -0400288
289 if (fl->fl_lmops) {
290 if (fl->fl_lmops->lm_get_owner)
291 fl->fl_lmops->lm_get_owner(new, fl);
292 }
Trond Myklebust09969052006-03-20 13:44:38 -0500293}
Kinglong Mee3fe0fff12014-08-22 10:18:42 -0400294EXPORT_SYMBOL(locks_copy_conflock);
Trond Myklebust09969052006-03-20 13:44:38 -0500295
296void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
297{
Jeff Layton566709b2014-08-11 14:09:35 -0400298 /* "new" must be a freshly-initialized lock */
299 WARN_ON_ONCE(new->fl_ops);
Trond Myklebust09969052006-03-20 13:44:38 -0500300
Kinglong Mee3fe0fff12014-08-22 10:18:42 -0400301 locks_copy_conflock(new, fl);
Kinglong Meef3282962014-08-22 10:18:43 -0400302
Trond Myklebust09969052006-03-20 13:44:38 -0500303 new->fl_file = fl->fl_file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 new->fl_ops = fl->fl_ops;
Trond Myklebust47831f32006-03-20 13:44:05 -0500305
Kinglong Meef3282962014-08-22 10:18:43 -0400306 if (fl->fl_ops) {
307 if (fl->fl_ops->fl_copy_lock)
308 fl->fl_ops->fl_copy_lock(new, fl);
309 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310}
311
312EXPORT_SYMBOL(locks_copy_lock);
313
314static inline int flock_translate_cmd(int cmd) {
315 if (cmd & LOCK_MAND)
316 return cmd & (LOCK_MAND | LOCK_RW);
317 switch (cmd) {
318 case LOCK_SH:
319 return F_RDLCK;
320 case LOCK_EX:
321 return F_WRLCK;
322 case LOCK_UN:
323 return F_UNLCK;
324 }
325 return -EINVAL;
326}
327
328/* Fill in a file_lock structure with an appropriate FLOCK lock. */
329static int flock_make_lock(struct file *filp, struct file_lock **lock,
330 unsigned int cmd)
331{
332 struct file_lock *fl;
333 int type = flock_translate_cmd(cmd);
334 if (type < 0)
335 return type;
336
337 fl = locks_alloc_lock();
338 if (fl == NULL)
339 return -ENOMEM;
340
341 fl->fl_file = filp;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +0200342 fl->fl_owner = filp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343 fl->fl_pid = current->tgid;
344 fl->fl_flags = FL_FLOCK;
345 fl->fl_type = type;
346 fl->fl_end = OFFSET_MAX;
347
348 *lock = fl;
349 return 0;
350}
351
J. Bruce Fields0ec4f432012-07-23 15:17:17 -0400352static int assign_type(struct file_lock *fl, long type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353{
354 switch (type) {
355 case F_RDLCK:
356 case F_WRLCK:
357 case F_UNLCK:
358 fl->fl_type = type;
359 break;
360 default:
361 return -EINVAL;
362 }
363 return 0;
364}
365
J. Bruce Fieldsef12e722014-02-03 12:13:08 -0500366static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
367 struct flock64 *l)
368{
369 switch (l->l_whence) {
370 case SEEK_SET:
371 fl->fl_start = 0;
372 break;
373 case SEEK_CUR:
374 fl->fl_start = filp->f_pos;
375 break;
376 case SEEK_END:
377 fl->fl_start = i_size_read(file_inode(filp));
378 break;
379 default:
380 return -EINVAL;
381 }
382 if (l->l_start > OFFSET_MAX - fl->fl_start)
383 return -EOVERFLOW;
384 fl->fl_start += l->l_start;
385 if (fl->fl_start < 0)
386 return -EINVAL;
387
388 /* POSIX-1996 leaves the case l->l_len < 0 undefined;
389 POSIX-2001 defines it. */
390 if (l->l_len > 0) {
391 if (l->l_len - 1 > OFFSET_MAX - fl->fl_start)
392 return -EOVERFLOW;
393 fl->fl_end = fl->fl_start + l->l_len - 1;
394
395 } else if (l->l_len < 0) {
396 if (fl->fl_start + l->l_len < 0)
397 return -EINVAL;
398 fl->fl_end = fl->fl_start - 1;
399 fl->fl_start += l->l_len;
400 } else
401 fl->fl_end = OFFSET_MAX;
402
403 fl->fl_owner = current->files;
404 fl->fl_pid = current->tgid;
405 fl->fl_file = filp;
406 fl->fl_flags = FL_POSIX;
407 fl->fl_ops = NULL;
408 fl->fl_lmops = NULL;
409
410 return assign_type(fl, l->l_type);
411}
412
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413/* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX
414 * style lock.
415 */
416static int flock_to_posix_lock(struct file *filp, struct file_lock *fl,
417 struct flock *l)
418{
J. Bruce Fieldsef12e722014-02-03 12:13:08 -0500419 struct flock64 ll = {
420 .l_type = l->l_type,
421 .l_whence = l->l_whence,
422 .l_start = l->l_start,
423 .l_len = l->l_len,
424 };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425
J. Bruce Fieldsef12e722014-02-03 12:13:08 -0500426 return flock64_to_posix_lock(filp, fl, &ll);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427}
428
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429/* default lease lock manager operations */
430static void lease_break_callback(struct file_lock *fl)
431{
432 kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG);
433}
434
Jeff Layton1c7dd2f2014-08-22 10:55:47 -0400435static void
436lease_setup(struct file_lock *fl, void **priv)
437{
438 struct file *filp = fl->fl_file;
439 struct fasync_struct *fa = *priv;
440
441 /*
442 * fasync_insert_entry() returns the old entry if any. If there was no
443 * old entry, then it used "priv" and inserted it into the fasync list.
444 * Clear the pointer to indicate that it shouldn't be freed.
445 */
446 if (!fasync_insert_entry(fa->fa_fd, filp, &fl->fl_fasync, fa))
447 *priv = NULL;
448
449 __f_setown(filp, task_pid(current), PIDTYPE_PID, 0);
450}
451
Alexey Dobriyan7b021962009-09-21 17:01:12 -0700452static const struct lock_manager_operations lease_manager_ops = {
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400453 .lm_break = lease_break_callback,
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400454 .lm_change = lease_modify,
Jeff Layton1c7dd2f2014-08-22 10:55:47 -0400455 .lm_setup = lease_setup,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456};
457
458/*
459 * Initialize a lease, use the default lock manager operations
460 */
J. Bruce Fields0ec4f432012-07-23 15:17:17 -0400461static int lease_init(struct file *filp, long type, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462 {
Trond Myklebust75dff552006-05-07 23:02:42 -0400463 if (assign_type(fl, type) != 0)
464 return -EINVAL;
465
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +0200466 fl->fl_owner = current->files;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467 fl->fl_pid = current->tgid;
468
469 fl->fl_file = filp;
470 fl->fl_flags = FL_LEASE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471 fl->fl_start = 0;
472 fl->fl_end = OFFSET_MAX;
473 fl->fl_ops = NULL;
474 fl->fl_lmops = &lease_manager_ops;
475 return 0;
476}
477
478/* Allocate a file_lock initialised to this type of lease */
J. Bruce Fields0ec4f432012-07-23 15:17:17 -0400479static struct file_lock *lease_alloc(struct file *filp, long type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480{
481 struct file_lock *fl = locks_alloc_lock();
Trond Myklebust75dff552006-05-07 23:02:42 -0400482 int error = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483
484 if (fl == NULL)
J. Bruce Fieldse32b8ee2007-03-01 14:34:35 -0500485 return ERR_PTR(error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486
487 error = lease_init(filp, type, fl);
Trond Myklebust75dff552006-05-07 23:02:42 -0400488 if (error) {
489 locks_free_lock(fl);
J. Bruce Fieldse32b8ee2007-03-01 14:34:35 -0500490 return ERR_PTR(error);
Trond Myklebust75dff552006-05-07 23:02:42 -0400491 }
J. Bruce Fieldse32b8ee2007-03-01 14:34:35 -0500492 return fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493}
494
495/* Check if two locks overlap each other.
496 */
497static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2)
498{
499 return ((fl1->fl_end >= fl2->fl_start) &&
500 (fl2->fl_end >= fl1->fl_start));
501}
502
503/*
504 * Check whether two locks have the same owner.
505 */
Matt Mackall33443c42006-01-08 01:05:22 -0800506static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507{
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400508 if (fl1->fl_lmops && fl1->fl_lmops->lm_compare_owner)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509 return fl2->fl_lmops == fl1->fl_lmops &&
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400510 fl1->fl_lmops->lm_compare_owner(fl1, fl2);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 return fl1->fl_owner == fl2->fl_owner;
512}
513
Jeff Layton7012b022013-06-21 08:58:22 -0400514/* Must be called with the i_lock held! */
Jeff Layton6ca10ed2014-02-03 12:13:07 -0500515static void locks_insert_global_locks(struct file_lock *fl)
Jeff Layton88974692013-06-21 08:58:14 -0400516{
Jeff Layton7012b022013-06-21 08:58:22 -0400517 lg_local_lock(&file_lock_lglock);
518 fl->fl_link_cpu = smp_processor_id();
519 hlist_add_head(&fl->fl_link, this_cpu_ptr(&file_lock_list));
520 lg_local_unlock(&file_lock_lglock);
Jeff Layton88974692013-06-21 08:58:14 -0400521}
522
Jeff Layton7012b022013-06-21 08:58:22 -0400523/* Must be called with the i_lock held! */
Jeff Layton6ca10ed2014-02-03 12:13:07 -0500524static void locks_delete_global_locks(struct file_lock *fl)
Jeff Layton88974692013-06-21 08:58:14 -0400525{
Jeff Layton7012b022013-06-21 08:58:22 -0400526 /*
527 * Avoid taking lock if already unhashed. This is safe since this check
528 * is done while holding the i_lock, and new insertions into the list
529 * also require that it be held.
530 */
531 if (hlist_unhashed(&fl->fl_link))
532 return;
533 lg_local_lock_cpu(&file_lock_lglock, fl->fl_link_cpu);
Jeff Layton139ca042013-06-21 08:58:17 -0400534 hlist_del_init(&fl->fl_link);
Jeff Layton7012b022013-06-21 08:58:22 -0400535 lg_local_unlock_cpu(&file_lock_lglock, fl->fl_link_cpu);
Jeff Layton88974692013-06-21 08:58:14 -0400536}
537
Jeff Layton3999e492013-06-21 08:58:19 -0400538static unsigned long
539posix_owner_key(struct file_lock *fl)
540{
541 if (fl->fl_lmops && fl->fl_lmops->lm_owner_key)
542 return fl->fl_lmops->lm_owner_key(fl);
543 return (unsigned long)fl->fl_owner;
544}
545
Jeff Layton6ca10ed2014-02-03 12:13:07 -0500546static void locks_insert_global_blocked(struct file_lock *waiter)
Jeff Layton88974692013-06-21 08:58:14 -0400547{
Jeff Layton3999e492013-06-21 08:58:19 -0400548 hash_add(blocked_hash, &waiter->fl_link, posix_owner_key(waiter));
Jeff Layton88974692013-06-21 08:58:14 -0400549}
550
Jeff Layton6ca10ed2014-02-03 12:13:07 -0500551static void locks_delete_global_blocked(struct file_lock *waiter)
Jeff Layton88974692013-06-21 08:58:14 -0400552{
Jeff Layton48f74182013-06-21 08:58:18 -0400553 hash_del(&waiter->fl_link);
Jeff Layton88974692013-06-21 08:58:14 -0400554}
555
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556/* Remove waiter from blocker's block list.
557 * When blocker ends up pointing to itself then the list is empty.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400558 *
Jeff Layton7b2296a2013-06-21 08:58:20 -0400559 * Must be called with blocked_lock_lock held.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 */
Matt Mackall33443c42006-01-08 01:05:22 -0800561static void __locks_delete_block(struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562{
Jeff Layton88974692013-06-21 08:58:14 -0400563 locks_delete_global_blocked(waiter);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564 list_del_init(&waiter->fl_block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565 waiter->fl_next = NULL;
566}
567
Jeff Layton1a9e64a2013-06-21 08:58:10 -0400568static void locks_delete_block(struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569{
Jeff Layton7b2296a2013-06-21 08:58:20 -0400570 spin_lock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571 __locks_delete_block(waiter);
Jeff Layton7b2296a2013-06-21 08:58:20 -0400572 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573}
574
575/* Insert waiter into blocker's block list.
576 * We use a circular list so that processes can be easily woken up in
577 * the order they blocked. The documentation doesn't require this but
578 * it seems like the reasonable thing to do.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400579 *
Jeff Layton7b2296a2013-06-21 08:58:20 -0400580 * Must be called with both the i_lock and blocked_lock_lock held. The fl_block
Jeff Layton46dad762014-02-03 12:13:06 -0500581 * list itself is protected by the blocked_lock_lock, but by ensuring that the
Jeff Layton7b2296a2013-06-21 08:58:20 -0400582 * i_lock is also held on insertions we can avoid taking the blocked_lock_lock
Jeff Layton4e8c7652013-06-21 08:58:16 -0400583 * in some cases when we see that the fl_block list is empty.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584 */
Jeff Layton1c8c6012013-06-21 08:58:15 -0400585static void __locks_insert_block(struct file_lock *blocker,
586 struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587{
J. Bruce Fields6dc0fe82006-03-26 01:37:24 -0800588 BUG_ON(!list_empty(&waiter->fl_block));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 waiter->fl_next = blocker;
Jeff Layton88974692013-06-21 08:58:14 -0400590 list_add_tail(&waiter->fl_block, &blocker->fl_block);
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400591 if (IS_POSIX(blocker) && !IS_OFDLCK(blocker))
Jeff Layton1c8c6012013-06-21 08:58:15 -0400592 locks_insert_global_blocked(waiter);
593}
594
595/* Must be called with i_lock held. */
596static void locks_insert_block(struct file_lock *blocker,
597 struct file_lock *waiter)
598{
Jeff Layton7b2296a2013-06-21 08:58:20 -0400599 spin_lock(&blocked_lock_lock);
Jeff Layton1c8c6012013-06-21 08:58:15 -0400600 __locks_insert_block(blocker, waiter);
Jeff Layton7b2296a2013-06-21 08:58:20 -0400601 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602}
603
Jeff Layton1cb36012013-06-21 08:58:12 -0400604/*
605 * Wake up processes blocked waiting for blocker.
606 *
Jeff Layton1c8c6012013-06-21 08:58:15 -0400607 * Must be called with the inode->i_lock held!
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 */
609static void locks_wake_up_blocks(struct file_lock *blocker)
610{
Jeff Layton4e8c7652013-06-21 08:58:16 -0400611 /*
612 * Avoid taking global lock if list is empty. This is safe since new
613 * blocked requests are only added to the list under the i_lock, and
614 * the i_lock is always held here. Note that removal from the fl_block
615 * list does not require the i_lock, so we must recheck list_empty()
Jeff Layton7b2296a2013-06-21 08:58:20 -0400616 * after acquiring the blocked_lock_lock.
Jeff Layton4e8c7652013-06-21 08:58:16 -0400617 */
618 if (list_empty(&blocker->fl_block))
619 return;
620
Jeff Layton7b2296a2013-06-21 08:58:20 -0400621 spin_lock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622 while (!list_empty(&blocker->fl_block)) {
Pavel Emelyanovf0c1cd02007-09-19 16:44:07 +0400623 struct file_lock *waiter;
624
625 waiter = list_first_entry(&blocker->fl_block,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626 struct file_lock, fl_block);
627 __locks_delete_block(waiter);
J. Bruce Fields8fb47a42011-07-20 20:21:59 -0400628 if (waiter->fl_lmops && waiter->fl_lmops->lm_notify)
629 waiter->fl_lmops->lm_notify(waiter);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630 else
631 wake_up(&waiter->fl_wait);
632 }
Jeff Layton7b2296a2013-06-21 08:58:20 -0400633 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634}
635
636/* Insert file lock fl into an inode's lock list at the position indicated
637 * by pos. At the same time add the lock to the global file lock list.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400638 *
639 * Must be called with the i_lock held!
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640 */
641static void locks_insert_lock(struct file_lock **pos, struct file_lock *fl)
642{
Vitaliy Gusevab1f1612008-01-17 00:07:08 +0000643 fl->fl_nspid = get_pid(task_tgid(current));
644
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645 /* insert into file's list */
646 fl->fl_next = *pos;
647 *pos = fl;
Jeff Layton88974692013-06-21 08:58:14 -0400648
649 locks_insert_global_locks(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650}
651
Jeff Layton24cbe782014-02-03 12:13:06 -0500652/**
653 * locks_delete_lock - Delete a lock and then free it.
654 * @thisfl_p: pointer that points to the fl_next field of the previous
655 * inode->i_flock list entry
656 *
657 * Unlink a lock from all lists and free the namespace reference, but don't
658 * free it yet. Wake up processes that are blocked waiting for this lock and
659 * notify the FS that the lock has been cleared.
Jeff Layton1c8c6012013-06-21 08:58:15 -0400660 *
661 * Must be called with the i_lock held!
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662 */
Jeff Layton24cbe782014-02-03 12:13:06 -0500663static void locks_unlink_lock(struct file_lock **thisfl_p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664{
665 struct file_lock *fl = *thisfl_p;
666
Jeff Layton88974692013-06-21 08:58:14 -0400667 locks_delete_global_locks(fl);
668
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669 *thisfl_p = fl->fl_next;
670 fl->fl_next = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671
Vitaliy Gusevab1f1612008-01-17 00:07:08 +0000672 if (fl->fl_nspid) {
673 put_pid(fl->fl_nspid);
674 fl->fl_nspid = NULL;
675 }
676
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677 locks_wake_up_blocks(fl);
Jeff Layton24cbe782014-02-03 12:13:06 -0500678}
679
680/*
681 * Unlink a lock from all lists and free it.
682 *
683 * Must be called with i_lock held!
684 */
Jeff Laytoned9814d2014-08-11 14:20:31 -0400685static void locks_delete_lock(struct file_lock **thisfl_p,
686 struct list_head *dispose)
Jeff Layton24cbe782014-02-03 12:13:06 -0500687{
688 struct file_lock *fl = *thisfl_p;
689
690 locks_unlink_lock(thisfl_p);
Jeff Laytoned9814d2014-08-11 14:20:31 -0400691 if (dispose)
692 list_add(&fl->fl_block, dispose);
693 else
694 locks_free_lock(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700695}
696
697/* Determine if lock sys_fl blocks lock caller_fl. Common functionality
698 * checks for shared/exclusive status of overlapping locks.
699 */
700static int locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
701{
702 if (sys_fl->fl_type == F_WRLCK)
703 return 1;
704 if (caller_fl->fl_type == F_WRLCK)
705 return 1;
706 return 0;
707}
708
709/* Determine if lock sys_fl blocks lock caller_fl. POSIX specific
710 * checking before calling the locks_conflict().
711 */
712static int posix_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
713{
714 /* POSIX locks owned by the same process do not conflict with
715 * each other.
716 */
717 if (!IS_POSIX(sys_fl) || posix_same_owner(caller_fl, sys_fl))
718 return (0);
719
720 /* Check whether they overlap */
721 if (!locks_overlap(caller_fl, sys_fl))
722 return 0;
723
724 return (locks_conflict(caller_fl, sys_fl));
725}
726
727/* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific
728 * checking before calling the locks_conflict().
729 */
730static int flock_locks_conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
731{
732 /* FLOCK locks referring to the same filp do not conflict with
733 * each other.
734 */
735 if (!IS_FLOCK(sys_fl) || (caller_fl->fl_file == sys_fl->fl_file))
736 return (0);
737 if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND))
738 return 0;
739
740 return (locks_conflict(caller_fl, sys_fl));
741}
742
J. Bruce Fields6d34ac12007-05-11 16:09:32 -0400743void
Marc Eshel9d6a8c52007-02-21 00:55:18 -0500744posix_test_lock(struct file *filp, struct file_lock *fl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700745{
746 struct file_lock *cfl;
Jeff Layton1c8c6012013-06-21 08:58:15 -0400747 struct inode *inode = file_inode(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748
Jeff Layton1c8c6012013-06-21 08:58:15 -0400749 spin_lock(&inode->i_lock);
Al Viro496ad9a2013-01-23 17:07:38 -0500750 for (cfl = file_inode(filp)->i_flock; cfl; cfl = cfl->fl_next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700751 if (!IS_POSIX(cfl))
752 continue;
J. Bruce Fieldsb842e242007-05-10 19:02:07 -0400753 if (posix_locks_conflict(fl, cfl))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754 break;
755 }
Vitaliy Gusevab1f1612008-01-17 00:07:08 +0000756 if (cfl) {
Kinglong Mee3fe0fff12014-08-22 10:18:42 -0400757 locks_copy_conflock(fl, cfl);
Vitaliy Gusevab1f1612008-01-17 00:07:08 +0000758 if (cfl->fl_nspid)
Pavel Emelyanov6c5f3e72008-02-08 04:19:20 -0800759 fl->fl_pid = pid_vnr(cfl->fl_nspid);
Vitaliy Gusevab1f1612008-01-17 00:07:08 +0000760 } else
J. Bruce Fields129a84d2007-05-10 18:38:43 -0400761 fl->fl_type = F_UNLCK;
Jeff Layton1c8c6012013-06-21 08:58:15 -0400762 spin_unlock(&inode->i_lock);
J. Bruce Fields6d34ac12007-05-11 16:09:32 -0400763 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765EXPORT_SYMBOL(posix_test_lock);
766
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400767/*
768 * Deadlock detection:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769 *
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400770 * We attempt to detect deadlocks that are due purely to posix file
771 * locks.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700772 *
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400773 * We assume that a task can be waiting for at most one lock at a time.
774 * So for any acquired lock, the process holding that lock may be
775 * waiting on at most one other lock. That lock in turns may be held by
776 * someone waiting for at most one other lock. Given a requested lock
777 * caller_fl which is about to wait for a conflicting lock block_fl, we
778 * follow this chain of waiters to ensure we are not about to create a
779 * cycle.
J. Bruce Fields97855b42007-10-30 11:20:02 -0400780 *
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400781 * Since we do this before we ever put a process to sleep on a lock, we
782 * are ensured that there is never a cycle; that is what guarantees that
783 * the while() loop in posix_locks_deadlock() eventually completes.
784 *
785 * Note: the above assumption may not be true when handling lock
786 * requests from a broken NFS client. It may also fail in the presence
787 * of tasks (such as posix threads) sharing the same open file table.
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400788 * To handle those cases, we just bail out after a few iterations.
Jeff Layton57b65322014-02-03 12:13:09 -0500789 *
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400790 * For FL_OFDLCK locks, the owner is the filp, not the files_struct.
Jeff Layton57b65322014-02-03 12:13:09 -0500791 * Because the owner is not even nominally tied to a thread of
792 * execution, the deadlock detection below can't reasonably work well. Just
793 * skip it for those.
794 *
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400795 * In principle, we could do a more limited deadlock detection on FL_OFDLCK
Jeff Layton57b65322014-02-03 12:13:09 -0500796 * locks that just checks for the case where two tasks are attempting to
797 * upgrade from read to write locks on the same inode.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798 */
J. Bruce Fields97855b42007-10-30 11:20:02 -0400799
800#define MAX_DEADLK_ITERATIONS 10
801
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400802/* Find a lock that the owner of the given block_fl is blocking on. */
803static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl)
804{
805 struct file_lock *fl;
806
Jeff Layton3999e492013-06-21 08:58:19 -0400807 hash_for_each_possible(blocked_hash, fl, fl_link, posix_owner_key(block_fl)) {
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400808 if (posix_same_owner(fl, block_fl))
809 return fl->fl_next;
810 }
811 return NULL;
812}
813
Jeff Layton7b2296a2013-06-21 08:58:20 -0400814/* Must be called with the blocked_lock_lock held! */
Adrian Bunkb0904e12006-06-23 02:05:13 -0700815static int posix_locks_deadlock(struct file_lock *caller_fl,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816 struct file_lock *block_fl)
817{
J. Bruce Fields97855b42007-10-30 11:20:02 -0400818 int i = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700819
Jeff Layton57b65322014-02-03 12:13:09 -0500820 /*
821 * This deadlock detector can't reasonably detect deadlocks with
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400822 * FL_OFDLCK locks, since they aren't owned by a process, per-se.
Jeff Layton57b65322014-02-03 12:13:09 -0500823 */
Jeff Laytoncff2fce2014-04-22 08:24:32 -0400824 if (IS_OFDLCK(caller_fl))
Jeff Layton57b65322014-02-03 12:13:09 -0500825 return 0;
826
J. Bruce Fieldsb5331842007-10-26 18:05:40 -0400827 while ((block_fl = what_owner_is_waiting_for(block_fl))) {
828 if (i++ > MAX_DEADLK_ITERATIONS)
829 return 0;
830 if (posix_same_owner(caller_fl, block_fl))
831 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832 }
833 return 0;
834}
835
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836/* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
J. Bruce Fields02888f42007-09-12 15:45:07 -0400837 * after any leases, but before any posix locks.
Trond Myklebustf475ae92006-06-29 16:38:32 -0400838 *
839 * Note that if called with an FL_EXISTS argument, the caller may determine
840 * whether or not a lock was successfully freed by testing the return
841 * value for -ENOENT.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842 */
Trond Myklebust993dfa82006-03-31 02:30:55 -0800843static int flock_lock_file(struct file *filp, struct file_lock *request)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844{
Trond Myklebust993dfa82006-03-31 02:30:55 -0800845 struct file_lock *new_fl = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846 struct file_lock **before;
Al Viro496ad9a2013-01-23 17:07:38 -0500847 struct inode * inode = file_inode(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848 int error = 0;
849 int found = 0;
Jeff Laytoned9814d2014-08-11 14:20:31 -0400850 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700851
Arnd Bergmannb89f4322010-09-18 15:09:31 +0200852 if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) {
853 new_fl = locks_alloc_lock();
854 if (!new_fl)
855 return -ENOMEM;
856 }
857
Jeff Layton1c8c6012013-06-21 08:58:15 -0400858 spin_lock(&inode->i_lock);
Trond Myklebustf07f18d2006-06-29 16:38:37 -0400859 if (request->fl_flags & FL_ACCESS)
860 goto find_conflict;
Pavel Emelyanov84d535a2007-09-11 16:38:13 +0400861
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862 for_each_lock(inode, before) {
863 struct file_lock *fl = *before;
864 if (IS_POSIX(fl))
865 break;
866 if (IS_LEASE(fl))
867 continue;
868 if (filp != fl->fl_file)
869 continue;
Trond Myklebust993dfa82006-03-31 02:30:55 -0800870 if (request->fl_type == fl->fl_type)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700871 goto out;
872 found = 1;
Jeff Laytoned9814d2014-08-11 14:20:31 -0400873 locks_delete_lock(before, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700874 break;
875 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876
Trond Myklebustf475ae92006-06-29 16:38:32 -0400877 if (request->fl_type == F_UNLCK) {
878 if ((request->fl_flags & FL_EXISTS) && !found)
879 error = -ENOENT;
Trond Myklebust993dfa82006-03-31 02:30:55 -0800880 goto out;
Trond Myklebustf475ae92006-06-29 16:38:32 -0400881 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882
883 /*
884 * If a higher-priority process was blocked on the old file lock,
885 * give it the opportunity to lock the file.
886 */
Arnd Bergmannb89f4322010-09-18 15:09:31 +0200887 if (found) {
Jeff Layton1c8c6012013-06-21 08:58:15 -0400888 spin_unlock(&inode->i_lock);
Frederic Weisbeckerdef01bc2009-07-16 15:44:29 +0200889 cond_resched();
Jeff Layton1c8c6012013-06-21 08:58:15 -0400890 spin_lock(&inode->i_lock);
Arnd Bergmannb89f4322010-09-18 15:09:31 +0200891 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892
Trond Myklebustf07f18d2006-06-29 16:38:37 -0400893find_conflict:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700894 for_each_lock(inode, before) {
895 struct file_lock *fl = *before;
896 if (IS_POSIX(fl))
897 break;
898 if (IS_LEASE(fl))
899 continue;
Trond Myklebust993dfa82006-03-31 02:30:55 -0800900 if (!flock_locks_conflict(request, fl))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700901 continue;
902 error = -EAGAIN;
Miklos Szeredibde74e42008-07-25 01:48:57 -0700903 if (!(request->fl_flags & FL_SLEEP))
904 goto out;
905 error = FILE_LOCK_DEFERRED;
906 locks_insert_block(fl, request);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700907 goto out;
908 }
Trond Myklebustf07f18d2006-06-29 16:38:37 -0400909 if (request->fl_flags & FL_ACCESS)
910 goto out;
Trond Myklebust993dfa82006-03-31 02:30:55 -0800911 locks_copy_lock(new_fl, request);
Pavel Emelyanov0e2f6db2007-09-11 15:24:01 -0700912 locks_insert_lock(before, new_fl);
Trond Myklebust993dfa82006-03-31 02:30:55 -0800913 new_fl = NULL;
Kirill Korotaev9cedc192006-06-14 17:59:35 +0400914 error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915
916out:
Jeff Layton1c8c6012013-06-21 08:58:15 -0400917 spin_unlock(&inode->i_lock);
Trond Myklebust993dfa82006-03-31 02:30:55 -0800918 if (new_fl)
919 locks_free_lock(new_fl);
Jeff Laytoned9814d2014-08-11 14:20:31 -0400920 locks_dispose_list(&dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700921 return error;
922}
923
Marc Eshel150b3932007-01-18 16:15:35 -0500924static int __posix_lock_file(struct inode *inode, struct file_lock *request, struct file_lock *conflock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700925{
926 struct file_lock *fl;
Miklos Szeredi39005d02006-06-23 02:05:10 -0700927 struct file_lock *new_fl = NULL;
928 struct file_lock *new_fl2 = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929 struct file_lock *left = NULL;
930 struct file_lock *right = NULL;
931 struct file_lock **before;
Jeff Laytonb9746ef2013-06-21 08:58:13 -0400932 int error;
933 bool added = false;
Jeff Laytoned9814d2014-08-11 14:20:31 -0400934 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935
936 /*
937 * We may need two file_lock structures for this operation,
938 * so we get them in advance to avoid races.
Miklos Szeredi39005d02006-06-23 02:05:10 -0700939 *
940 * In some cases we can be sure, that no new locks will be needed
Linus Torvalds1da177e2005-04-16 15:20:36 -0700941 */
Miklos Szeredi39005d02006-06-23 02:05:10 -0700942 if (!(request->fl_flags & FL_ACCESS) &&
943 (request->fl_type != F_UNLCK ||
944 request->fl_start != 0 || request->fl_end != OFFSET_MAX)) {
945 new_fl = locks_alloc_lock();
946 new_fl2 = locks_alloc_lock();
947 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700948
Jeff Layton1c8c6012013-06-21 08:58:15 -0400949 spin_lock(&inode->i_lock);
Jeff Layton1cb36012013-06-21 08:58:12 -0400950 /*
951 * New lock request. Walk all POSIX locks and look for conflicts. If
952 * there are any, either return error or put the request on the
Jeff Layton48f74182013-06-21 08:58:18 -0400953 * blocker's list of waiters and the global blocked_hash.
Jeff Layton1cb36012013-06-21 08:58:12 -0400954 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955 if (request->fl_type != F_UNLCK) {
956 for_each_lock(inode, before) {
J. Bruce Fields526985b2006-11-14 16:54:36 -0500957 fl = *before;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700958 if (!IS_POSIX(fl))
959 continue;
960 if (!posix_locks_conflict(request, fl))
961 continue;
Andy Adamson5842add2006-03-26 01:37:26 -0800962 if (conflock)
Kinglong Mee3fe0fff12014-08-22 10:18:42 -0400963 locks_copy_conflock(conflock, fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964 error = -EAGAIN;
965 if (!(request->fl_flags & FL_SLEEP))
966 goto out;
Jeff Layton1c8c6012013-06-21 08:58:15 -0400967 /*
968 * Deadlock detection and insertion into the blocked
969 * locks list must be done while holding the same lock!
970 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700971 error = -EDEADLK;
Jeff Layton7b2296a2013-06-21 08:58:20 -0400972 spin_lock(&blocked_lock_lock);
Jeff Layton1c8c6012013-06-21 08:58:15 -0400973 if (likely(!posix_locks_deadlock(request, fl))) {
974 error = FILE_LOCK_DEFERRED;
975 __locks_insert_block(fl, request);
976 }
Jeff Layton7b2296a2013-06-21 08:58:20 -0400977 spin_unlock(&blocked_lock_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700978 goto out;
979 }
980 }
981
982 /* If we're just looking for a conflict, we're done. */
983 error = 0;
984 if (request->fl_flags & FL_ACCESS)
985 goto out;
986
Linus Torvalds1da177e2005-04-16 15:20:36 -0700987 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700988 * Find the first old lock with the same owner as the new lock.
989 */
990
991 before = &inode->i_flock;
992
993 /* First skip locks owned by other processes. */
994 while ((fl = *before) && (!IS_POSIX(fl) ||
995 !posix_same_owner(request, fl))) {
996 before = &fl->fl_next;
997 }
998
Jeff Layton1cb36012013-06-21 08:58:12 -0400999 /* Process locks with this owner. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001000 while ((fl = *before) && posix_same_owner(request, fl)) {
1001 /* Detect adjacent or overlapping regions (if same lock type)
1002 */
1003 if (request->fl_type == fl->fl_type) {
Olaf Kirch449231d2005-08-25 16:25:35 -07001004 /* In all comparisons of start vs end, use
1005 * "start - 1" rather than "end + 1". If end
1006 * is OFFSET_MAX, end + 1 will become negative.
1007 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001008 if (fl->fl_end < request->fl_start - 1)
1009 goto next_lock;
1010 /* If the next lock in the list has entirely bigger
1011 * addresses than the new one, insert the lock here.
1012 */
Olaf Kirch449231d2005-08-25 16:25:35 -07001013 if (fl->fl_start - 1 > request->fl_end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 break;
1015
1016 /* If we come here, the new and old lock are of the
1017 * same type and adjacent or overlapping. Make one
1018 * lock yielding from the lower start address of both
1019 * locks to the higher end address.
1020 */
1021 if (fl->fl_start > request->fl_start)
1022 fl->fl_start = request->fl_start;
1023 else
1024 request->fl_start = fl->fl_start;
1025 if (fl->fl_end < request->fl_end)
1026 fl->fl_end = request->fl_end;
1027 else
1028 request->fl_end = fl->fl_end;
1029 if (added) {
Jeff Laytoned9814d2014-08-11 14:20:31 -04001030 locks_delete_lock(before, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001031 continue;
1032 }
1033 request = fl;
Jeff Laytonb9746ef2013-06-21 08:58:13 -04001034 added = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001035 }
1036 else {
1037 /* Processing for different lock types is a bit
1038 * more complex.
1039 */
1040 if (fl->fl_end < request->fl_start)
1041 goto next_lock;
1042 if (fl->fl_start > request->fl_end)
1043 break;
1044 if (request->fl_type == F_UNLCK)
Jeff Laytonb9746ef2013-06-21 08:58:13 -04001045 added = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001046 if (fl->fl_start < request->fl_start)
1047 left = fl;
1048 /* If the next lock in the list has a higher end
1049 * address than the new one, insert the new one here.
1050 */
1051 if (fl->fl_end > request->fl_end) {
1052 right = fl;
1053 break;
1054 }
1055 if (fl->fl_start >= request->fl_start) {
1056 /* The new lock completely replaces an old
1057 * one (This may happen several times).
1058 */
1059 if (added) {
Jeff Laytoned9814d2014-08-11 14:20:31 -04001060 locks_delete_lock(before, &dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001061 continue;
1062 }
Jeff Laytonb84d49f2014-08-12 08:03:49 -04001063 /*
1064 * Replace the old lock with new_fl, and
1065 * remove the old one. It's safe to do the
1066 * insert here since we know that we won't be
1067 * using new_fl later, and that the lock is
1068 * just replacing an existing lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069 */
Jeff Laytonb84d49f2014-08-12 08:03:49 -04001070 error = -ENOLCK;
1071 if (!new_fl)
1072 goto out;
1073 locks_copy_lock(new_fl, request);
1074 request = new_fl;
1075 new_fl = NULL;
Jeff Laytoned9814d2014-08-11 14:20:31 -04001076 locks_delete_lock(before, &dispose);
Jeff Laytonb84d49f2014-08-12 08:03:49 -04001077 locks_insert_lock(before, request);
Jeff Laytonb9746ef2013-06-21 08:58:13 -04001078 added = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001079 }
1080 }
1081 /* Go on to next lock.
1082 */
1083 next_lock:
1084 before = &fl->fl_next;
1085 }
1086
Miklos Szeredi0d9a4902006-06-23 02:05:09 -07001087 /*
Jeff Layton1cb36012013-06-21 08:58:12 -04001088 * The above code only modifies existing locks in case of merging or
1089 * replacing. If new lock(s) need to be inserted all modifications are
1090 * done below this, so it's safe yet to bail out.
Miklos Szeredi0d9a4902006-06-23 02:05:09 -07001091 */
1092 error = -ENOLCK; /* "no luck" */
1093 if (right && left == right && !new_fl2)
1094 goto out;
1095
Linus Torvalds1da177e2005-04-16 15:20:36 -07001096 error = 0;
1097 if (!added) {
Trond Myklebustf475ae92006-06-29 16:38:32 -04001098 if (request->fl_type == F_UNLCK) {
1099 if (request->fl_flags & FL_EXISTS)
1100 error = -ENOENT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001101 goto out;
Trond Myklebustf475ae92006-06-29 16:38:32 -04001102 }
Miklos Szeredi0d9a4902006-06-23 02:05:09 -07001103
1104 if (!new_fl) {
1105 error = -ENOLCK;
1106 goto out;
1107 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001108 locks_copy_lock(new_fl, request);
1109 locks_insert_lock(before, new_fl);
1110 new_fl = NULL;
1111 }
1112 if (right) {
1113 if (left == right) {
1114 /* The new lock breaks the old one in two pieces,
1115 * so we have to use the second new lock.
1116 */
1117 left = new_fl2;
1118 new_fl2 = NULL;
1119 locks_copy_lock(left, right);
1120 locks_insert_lock(before, left);
1121 }
1122 right->fl_start = request->fl_end + 1;
1123 locks_wake_up_blocks(right);
1124 }
1125 if (left) {
1126 left->fl_end = request->fl_start - 1;
1127 locks_wake_up_blocks(left);
1128 }
1129 out:
Jeff Layton1c8c6012013-06-21 08:58:15 -04001130 spin_unlock(&inode->i_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001131 /*
1132 * Free any unused locks.
1133 */
1134 if (new_fl)
1135 locks_free_lock(new_fl);
1136 if (new_fl2)
1137 locks_free_lock(new_fl2);
Jeff Laytoned9814d2014-08-11 14:20:31 -04001138 locks_dispose_list(&dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001139 return error;
1140}
1141
1142/**
1143 * posix_lock_file - Apply a POSIX-style lock to a file
1144 * @filp: The file to apply the lock to
1145 * @fl: The lock to be applied
Marc Eshel150b3932007-01-18 16:15:35 -05001146 * @conflock: Place to return a copy of the conflicting lock, if found.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001147 *
1148 * Add a POSIX style lock to a file.
1149 * We merge adjacent & overlapping locks whenever possible.
1150 * POSIX locks are sorted by owner task, then by starting address
Trond Myklebustf475ae92006-06-29 16:38:32 -04001151 *
1152 * Note that if called with an FL_EXISTS argument, the caller may determine
1153 * whether or not a lock was successfully freed by testing the return
1154 * value for -ENOENT.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001155 */
Marc Eshel150b3932007-01-18 16:15:35 -05001156int posix_lock_file(struct file *filp, struct file_lock *fl,
Andy Adamson5842add2006-03-26 01:37:26 -08001157 struct file_lock *conflock)
1158{
Al Viro496ad9a2013-01-23 17:07:38 -05001159 return __posix_lock_file(file_inode(filp), fl, conflock);
Andy Adamson5842add2006-03-26 01:37:26 -08001160}
Marc Eshel150b3932007-01-18 16:15:35 -05001161EXPORT_SYMBOL(posix_lock_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162
1163/**
1164 * posix_lock_file_wait - Apply a POSIX-style lock to a file
1165 * @filp: The file to apply the lock to
1166 * @fl: The lock to be applied
1167 *
1168 * Add a POSIX style lock to a file.
1169 * We merge adjacent & overlapping locks whenever possible.
1170 * POSIX locks are sorted by owner task, then by starting address
1171 */
1172int posix_lock_file_wait(struct file *filp, struct file_lock *fl)
1173{
1174 int error;
1175 might_sleep ();
1176 for (;;) {
Marc Eshel150b3932007-01-18 16:15:35 -05001177 error = posix_lock_file(filp, fl, NULL);
Miklos Szeredibde74e42008-07-25 01:48:57 -07001178 if (error != FILE_LOCK_DEFERRED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001179 break;
1180 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1181 if (!error)
1182 continue;
1183
1184 locks_delete_block(fl);
1185 break;
1186 }
1187 return error;
1188}
1189EXPORT_SYMBOL(posix_lock_file_wait);
1190
1191/**
1192 * locks_mandatory_locked - Check for an active lock
Jeff Laytond7a06982014-03-10 09:54:15 -04001193 * @file: the file to check
Linus Torvalds1da177e2005-04-16 15:20:36 -07001194 *
1195 * Searches the inode's list of locks to find any POSIX locks which conflict.
1196 * This function is called from locks_verify_locked() only.
1197 */
Jeff Laytond7a06982014-03-10 09:54:15 -04001198int locks_mandatory_locked(struct file *file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001199{
Jeff Laytond7a06982014-03-10 09:54:15 -04001200 struct inode *inode = file_inode(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201 struct file_lock *fl;
1202
1203 /*
1204 * Search the lock list for this inode for any POSIX locks.
1205 */
Jeff Layton1c8c6012013-06-21 08:58:15 -04001206 spin_lock(&inode->i_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207 for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
1208 if (!IS_POSIX(fl))
1209 continue;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02001210 if (fl->fl_owner != current->files &&
1211 fl->fl_owner != file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001212 break;
1213 }
Jeff Layton1c8c6012013-06-21 08:58:15 -04001214 spin_unlock(&inode->i_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001215 return fl ? -EAGAIN : 0;
1216}
1217
1218/**
1219 * locks_mandatory_area - Check for a conflicting lock
1220 * @read_write: %FLOCK_VERIFY_WRITE for exclusive access, %FLOCK_VERIFY_READ
1221 * for shared
1222 * @inode: the file to check
1223 * @filp: how the file was opened (if it was)
1224 * @offset: start of area to check
1225 * @count: length of area to check
1226 *
1227 * Searches the inode's list of locks to find any POSIX locks which conflict.
1228 * This function is called from rw_verify_area() and
1229 * locks_verify_truncate().
1230 */
1231int locks_mandatory_area(int read_write, struct inode *inode,
1232 struct file *filp, loff_t offset,
1233 size_t count)
1234{
1235 struct file_lock fl;
1236 int error;
Jeff Layton29723ad2014-03-10 09:54:19 -04001237 bool sleep = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001238
1239 locks_init_lock(&fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001240 fl.fl_pid = current->tgid;
1241 fl.fl_file = filp;
1242 fl.fl_flags = FL_POSIX | FL_ACCESS;
1243 if (filp && !(filp->f_flags & O_NONBLOCK))
Jeff Layton29723ad2014-03-10 09:54:19 -04001244 sleep = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001245 fl.fl_type = (read_write == FLOCK_VERIFY_WRITE) ? F_WRLCK : F_RDLCK;
1246 fl.fl_start = offset;
1247 fl.fl_end = offset + count - 1;
1248
1249 for (;;) {
Jeff Layton29723ad2014-03-10 09:54:19 -04001250 if (filp) {
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02001251 fl.fl_owner = filp;
Jeff Layton29723ad2014-03-10 09:54:19 -04001252 fl.fl_flags &= ~FL_SLEEP;
1253 error = __posix_lock_file(inode, &fl, NULL);
1254 if (!error)
1255 break;
1256 }
1257
1258 if (sleep)
1259 fl.fl_flags |= FL_SLEEP;
1260 fl.fl_owner = current->files;
Marc Eshel150b3932007-01-18 16:15:35 -05001261 error = __posix_lock_file(inode, &fl, NULL);
Miklos Szeredibde74e42008-07-25 01:48:57 -07001262 if (error != FILE_LOCK_DEFERRED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001263 break;
1264 error = wait_event_interruptible(fl.fl_wait, !fl.fl_next);
1265 if (!error) {
1266 /*
1267 * If we've been sleeping someone might have
1268 * changed the permissions behind our back.
1269 */
Pavel Emelyanova16877c2007-10-01 14:41:11 -07001270 if (__mandatory_lock(inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271 continue;
1272 }
1273
1274 locks_delete_block(&fl);
1275 break;
1276 }
1277
1278 return error;
1279}
1280
1281EXPORT_SYMBOL(locks_mandatory_area);
1282
J. Bruce Fields778fc542011-07-26 18:25:49 -04001283static void lease_clear_pending(struct file_lock *fl, int arg)
1284{
1285 switch (arg) {
1286 case F_UNLCK:
1287 fl->fl_flags &= ~FL_UNLOCK_PENDING;
1288 /* fall through: */
1289 case F_RDLCK:
1290 fl->fl_flags &= ~FL_DOWNGRADE_PENDING;
1291 }
1292}
1293
Linus Torvalds1da177e2005-04-16 15:20:36 -07001294/* We already had a lease on this file; just change its type */
1295int lease_modify(struct file_lock **before, int arg)
1296{
1297 struct file_lock *fl = *before;
1298 int error = assign_type(fl, arg);
1299
1300 if (error)
1301 return error;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001302 lease_clear_pending(fl, arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001303 locks_wake_up_blocks(fl);
Filipe Brandenburger3b6e2722012-07-27 00:42:52 -04001304 if (arg == F_UNLCK) {
1305 struct file *filp = fl->fl_file;
1306
1307 f_delown(filp);
1308 filp->f_owner.signum = 0;
J. Bruce Fields96d6d592012-07-27 16:18:00 -04001309 fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync);
1310 if (fl->fl_fasync != NULL) {
1311 printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);
1312 fl->fl_fasync = NULL;
1313 }
Jeff Laytoned9814d2014-08-11 14:20:31 -04001314 locks_delete_lock(before, NULL);
Filipe Brandenburger3b6e2722012-07-27 00:42:52 -04001315 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001316 return 0;
1317}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318EXPORT_SYMBOL(lease_modify);
1319
J. Bruce Fields778fc542011-07-26 18:25:49 -04001320static bool past_time(unsigned long then)
1321{
1322 if (!then)
1323 /* 0 is a special value meaning "this never expires": */
1324 return false;
1325 return time_after(jiffies, then);
1326}
1327
Linus Torvalds1da177e2005-04-16 15:20:36 -07001328static void time_out_leases(struct inode *inode)
1329{
1330 struct file_lock **before;
1331 struct file_lock *fl;
1332
1333 before = &inode->i_flock;
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -04001334 while ((fl = *before) && IS_LEASE(fl) && lease_breaking(fl)) {
Jeff Layton62af4f12014-05-09 14:13:05 -04001335 trace_time_out_leases(inode, fl);
J. Bruce Fields778fc542011-07-26 18:25:49 -04001336 if (past_time(fl->fl_downgrade_time))
1337 lease_modify(before, F_RDLCK);
1338 if (past_time(fl->fl_break_time))
1339 lease_modify(before, F_UNLCK);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001340 if (fl == *before) /* lease_modify may have freed fl */
1341 before = &fl->fl_next;
1342 }
1343}
1344
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001345static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
1346{
1347 if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE))
1348 return false;
1349 return locks_conflict(breaker, lease);
1350}
1351
Linus Torvalds1da177e2005-04-16 15:20:36 -07001352/**
1353 * __break_lease - revoke all outstanding leases on file
1354 * @inode: the inode of the file to return
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001355 * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR:
1356 * break all leases
1357 * @type: FL_LEASE: break leases and delegations; FL_DELEG: break
1358 * only delegations
Linus Torvalds1da177e2005-04-16 15:20:36 -07001359 *
david m. richter87250dd2007-05-09 16:10:27 -04001360 * break_lease (inlined for speed) has checked there already is at least
1361 * some kind of lock (maybe a lease) on this file. Leases are broken on
1362 * a call to open() or truncate(). This function can sleep unless you
Linus Torvalds1da177e2005-04-16 15:20:36 -07001363 * specified %O_NONBLOCK to your open().
1364 */
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001365int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001366{
J. Bruce Fields778fc542011-07-26 18:25:49 -04001367 int error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001368 struct file_lock *new_fl, *flock;
1369 struct file_lock *fl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001370 unsigned long break_time;
1371 int i_have_this_lease = 0;
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001372 bool lease_conflict = false;
Al Viro8737c932009-12-24 06:47:55 -05001373 int want_write = (mode & O_ACCMODE) != O_RDONLY;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001374
Al Viro8737c932009-12-24 06:47:55 -05001375 new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK);
Linus Torvalds6d4b9e32011-12-26 10:25:26 -08001376 if (IS_ERR(new_fl))
1377 return PTR_ERR(new_fl);
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001378 new_fl->fl_flags = type;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001379
Jeff Layton1c8c6012013-06-21 08:58:15 -04001380 spin_lock(&inode->i_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001381
1382 time_out_leases(inode);
1383
1384 flock = inode->i_flock;
1385 if ((flock == NULL) || !IS_LEASE(flock))
1386 goto out;
1387
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001388 for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) {
1389 if (leases_conflict(fl, new_fl)) {
1390 lease_conflict = true;
1391 if (fl->fl_owner == current->files)
1392 i_have_this_lease = 1;
1393 }
1394 }
1395 if (!lease_conflict)
J. Bruce Fields778fc542011-07-26 18:25:49 -04001396 goto out;
1397
Linus Torvalds1da177e2005-04-16 15:20:36 -07001398 break_time = 0;
1399 if (lease_break_time > 0) {
1400 break_time = jiffies + lease_break_time * HZ;
1401 if (break_time == 0)
1402 break_time++; /* so that 0 means no break time */
1403 }
1404
1405 for (fl = flock; fl && IS_LEASE(fl); fl = fl->fl_next) {
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001406 if (!leases_conflict(fl, new_fl))
1407 continue;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001408 if (want_write) {
1409 if (fl->fl_flags & FL_UNLOCK_PENDING)
1410 continue;
1411 fl->fl_flags |= FL_UNLOCK_PENDING;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001412 fl->fl_break_time = break_time;
J. Bruce Fields778fc542011-07-26 18:25:49 -04001413 } else {
1414 if (lease_breaking(flock))
1415 continue;
1416 fl->fl_flags |= FL_DOWNGRADE_PENDING;
1417 fl->fl_downgrade_time = break_time;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001418 }
J. Bruce Fields778fc542011-07-26 18:25:49 -04001419 fl->fl_lmops->lm_break(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001420 }
1421
1422 if (i_have_this_lease || (mode & O_NONBLOCK)) {
Jeff Layton62af4f12014-05-09 14:13:05 -04001423 trace_break_lease_noblock(inode, new_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001424 error = -EWOULDBLOCK;
1425 goto out;
1426 }
1427
1428restart:
1429 break_time = flock->fl_break_time;
Jeff Laytonf1c6bb22014-04-15 06:17:49 -04001430 if (break_time != 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001431 break_time -= jiffies;
Jeff Laytonf1c6bb22014-04-15 06:17:49 -04001432 if (break_time == 0)
1433 break_time++;
Matthew Wilcox4321e012008-01-14 21:28:30 -07001434 locks_insert_block(flock, new_fl);
Jeff Layton62af4f12014-05-09 14:13:05 -04001435 trace_break_lease_block(inode, new_fl);
Jeff Layton1c8c6012013-06-21 08:58:15 -04001436 spin_unlock(&inode->i_lock);
Matthew Wilcox4321e012008-01-14 21:28:30 -07001437 error = wait_event_interruptible_timeout(new_fl->fl_wait,
1438 !new_fl->fl_next, break_time);
Jeff Layton1c8c6012013-06-21 08:58:15 -04001439 spin_lock(&inode->i_lock);
Jeff Layton62af4f12014-05-09 14:13:05 -04001440 trace_break_lease_unblock(inode, new_fl);
Jeff Layton1c8c6012013-06-21 08:58:15 -04001441 locks_delete_block(new_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001442 if (error >= 0) {
1443 if (error == 0)
1444 time_out_leases(inode);
J. Bruce Fields778fc542011-07-26 18:25:49 -04001445 /*
1446 * Wait for the next conflicting lease that has not been
1447 * broken yet
1448 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001449 for (flock = inode->i_flock; flock && IS_LEASE(flock);
1450 flock = flock->fl_next) {
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001451 if (leases_conflict(new_fl, flock))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001452 goto restart;
1453 }
1454 error = 0;
1455 }
1456
1457out:
Jeff Layton1c8c6012013-06-21 08:58:15 -04001458 spin_unlock(&inode->i_lock);
Linus Torvalds6d4b9e32011-12-26 10:25:26 -08001459 locks_free_lock(new_fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001460 return error;
1461}
1462
1463EXPORT_SYMBOL(__break_lease);
1464
1465/**
Randy Dunlapa6b91912008-03-19 17:01:00 -07001466 * lease_get_mtime - get the last modified time of an inode
Linus Torvalds1da177e2005-04-16 15:20:36 -07001467 * @inode: the inode
1468 * @time: pointer to a timespec which will contain the last modified time
1469 *
1470 * This is to force NFS clients to flush their caches for files with
1471 * exclusive leases. The justification is that if someone has an
Randy Dunlapa6b91912008-03-19 17:01:00 -07001472 * exclusive lease, then they could be modifying it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001473 */
1474void lease_get_mtime(struct inode *inode, struct timespec *time)
1475{
Jeff Laytonbfe86022014-08-22 10:18:44 -04001476 bool has_lease = false;
1477 struct file_lock *flock;
1478
1479 if (inode->i_flock) {
1480 spin_lock(&inode->i_lock);
1481 flock = inode->i_flock;
1482 if (flock && IS_LEASE(flock) && (flock->fl_type == F_WRLCK))
1483 has_lease = true;
1484 spin_unlock(&inode->i_lock);
1485 }
1486
1487 if (has_lease)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001488 *time = current_fs_time(inode->i_sb);
1489 else
1490 *time = inode->i_mtime;
1491}
1492
1493EXPORT_SYMBOL(lease_get_mtime);
1494
1495/**
1496 * fcntl_getlease - Enquire what lease is currently active
1497 * @filp: the file
1498 *
1499 * The value returned by this function will be one of
1500 * (if no lease break is pending):
1501 *
1502 * %F_RDLCK to indicate a shared lease is held.
1503 *
1504 * %F_WRLCK to indicate an exclusive lease is held.
1505 *
1506 * %F_UNLCK to indicate no lease is held.
1507 *
1508 * (if a lease break is pending):
1509 *
1510 * %F_RDLCK to indicate an exclusive lease needs to be
1511 * changed to a shared lease (or removed).
1512 *
1513 * %F_UNLCK to indicate the lease needs to be removed.
1514 *
1515 * XXX: sfr & willy disagree over whether F_INPROGRESS
1516 * should be returned to userspace.
1517 */
1518int fcntl_getlease(struct file *filp)
1519{
1520 struct file_lock *fl;
Jeff Layton1c8c6012013-06-21 08:58:15 -04001521 struct inode *inode = file_inode(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001522 int type = F_UNLCK;
1523
Jeff Layton1c8c6012013-06-21 08:58:15 -04001524 spin_lock(&inode->i_lock);
Al Viro496ad9a2013-01-23 17:07:38 -05001525 time_out_leases(file_inode(filp));
1526 for (fl = file_inode(filp)->i_flock; fl && IS_LEASE(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001527 fl = fl->fl_next) {
1528 if (fl->fl_file == filp) {
J. Bruce Fields778fc542011-07-26 18:25:49 -04001529 type = target_leasetype(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001530 break;
1531 }
1532 }
Jeff Layton1c8c6012013-06-21 08:58:15 -04001533 spin_unlock(&inode->i_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001534 return type;
1535}
1536
Jeff Layton24cbe782014-02-03 12:13:06 -05001537/**
1538 * check_conflicting_open - see if the given dentry points to a file that has
1539 * an existing open that would conflict with the
1540 * desired lease.
1541 * @dentry: dentry to check
1542 * @arg: type of lease that we're trying to acquire
1543 *
1544 * Check to see if there's an existing open fd on this file that would
1545 * conflict with the lease we're trying to set.
1546 */
1547static int
1548check_conflicting_open(const struct dentry *dentry, const long arg)
1549{
1550 int ret = 0;
1551 struct inode *inode = dentry->d_inode;
1552
1553 if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
1554 return -EAGAIN;
1555
1556 if ((arg == F_WRLCK) && ((d_count(dentry) > 1) ||
1557 (atomic_read(&inode->i_count) > 1)))
1558 ret = -EAGAIN;
1559
1560 return ret;
1561}
1562
Jeff Laytone6f5c782014-08-22 10:40:25 -04001563static int
1564generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **priv)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001565{
KAMBAROV, ZAUR7eaae282005-07-07 17:57:06 -07001566 struct file_lock *fl, **before, **my_before = NULL, *lease;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -08001567 struct dentry *dentry = filp->f_path.dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001568 struct inode *inode = dentry->d_inode;
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001569 bool is_deleg = (*flp)->fl_flags & FL_DELEG;
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001570 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001571
J. Bruce Fields096657b2010-10-30 17:31:14 -04001572 lease = *flp;
Jeff Layton62af4f12014-05-09 14:13:05 -04001573 trace_generic_add_lease(inode, lease);
1574
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001575 /*
1576 * In the delegation case we need mutual exclusion with
1577 * a number of operations that take the i_mutex. We trylock
1578 * because delegations are an optional optimization, and if
1579 * there's some chance of a conflict--we'd rather not
1580 * bother, maybe that's a sign this just isn't a good file to
1581 * hand out a delegation on.
1582 */
1583 if (is_deleg && !mutex_trylock(&inode->i_mutex))
1584 return -EAGAIN;
1585
1586 if (is_deleg && arg == F_WRLCK) {
1587 /* Write delegations are not currently supported: */
Dan Carpenter4fdb7932013-11-13 10:56:27 +03001588 mutex_unlock(&inode->i_mutex);
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001589 WARN_ON_ONCE(1);
1590 return -EINVAL;
1591 }
J. Bruce Fields096657b2010-10-30 17:31:14 -04001592
Jeff Layton24cbe782014-02-03 12:13:06 -05001593 error = check_conflicting_open(dentry, arg);
1594 if (error)
J. Bruce Fields096657b2010-10-30 17:31:14 -04001595 goto out;
Pavel Emelyanov85c59582007-09-20 12:45:02 +04001596
Linus Torvalds1da177e2005-04-16 15:20:36 -07001597 /*
1598 * At this point, we know that if there is an exclusive
1599 * lease on this file, then we hold it on this filp
1600 * (otherwise our open of this file would have blocked).
1601 * And if we are trying to acquire an exclusive lease,
1602 * then the file is not open by anyone (including us)
1603 * except for this filp.
1604 */
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001605 error = -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001606 for (before = &inode->i_flock;
1607 ((fl = *before) != NULL) && IS_LEASE(fl);
1608 before = &fl->fl_next) {
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001609 if (fl->fl_file == filp) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001610 my_before = before;
J. Bruce Fieldsc1f24ef2011-08-19 10:59:49 -04001611 continue;
1612 }
1613 /*
1614 * No exclusive leases if someone else has a lease on
1615 * this file:
1616 */
1617 if (arg == F_WRLCK)
1618 goto out;
1619 /*
1620 * Modifying our existing lease is OK, but no getting a
1621 * new lease if someone else is opening for write:
1622 */
1623 if (fl->fl_flags & FL_UNLOCK_PENDING)
1624 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001625 }
1626
Linus Torvalds1da177e2005-04-16 15:20:36 -07001627 if (my_before != NULL) {
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001628 lease = *my_before;
J. Bruce Fields8fb47a42011-07-20 20:21:59 -04001629 error = lease->fl_lmops->lm_change(my_before, arg);
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001630 if (error)
1631 goto out;
1632 goto out_setup;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001633 }
1634
Linus Torvalds1da177e2005-04-16 15:20:36 -07001635 error = -EINVAL;
1636 if (!leases_enable)
1637 goto out;
1638
Arnd Bergmannc5b1f0d2010-10-27 15:46:08 +02001639 locks_insert_lock(before, lease);
Jeff Layton24cbe782014-02-03 12:13:06 -05001640 /*
1641 * The check in break_lease() is lockless. It's possible for another
1642 * open to race in after we did the earlier check for a conflicting
1643 * open but before the lease was inserted. Check again for a
1644 * conflicting open and cancel the lease if there is one.
1645 *
1646 * We also add a barrier here to ensure that the insertion of the lock
1647 * precedes these checks.
1648 */
1649 smp_mb();
1650 error = check_conflicting_open(dentry, arg);
1651 if (error)
Jeff Laytone6f5c782014-08-22 10:40:25 -04001652 goto out_unlink;
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001653
1654out_setup:
1655 if (lease->fl_lmops->lm_setup)
1656 lease->fl_lmops->lm_setup(lease, priv);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001657out:
J. Bruce Fieldsdf4e8d22012-03-05 13:18:59 -05001658 if (is_deleg)
1659 mutex_unlock(&inode->i_mutex);
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001660 if (!error && !my_before)
1661 *flp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001662 return error;
Jeff Laytone6f5c782014-08-22 10:40:25 -04001663out_unlink:
1664 locks_unlink_lock(before);
1665 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001666}
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001667
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001668static int generic_delete_lease(struct file *filp)
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001669{
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001670 int error = -EAGAIN;
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001671 struct file_lock *fl, **before;
1672 struct dentry *dentry = filp->f_path.dentry;
1673 struct inode *inode = dentry->d_inode;
1674
1675 for (before = &inode->i_flock;
1676 ((fl = *before) != NULL) && IS_LEASE(fl);
1677 before = &fl->fl_next) {
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001678 if (fl->fl_file == filp)
1679 break;
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001680 }
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001681 trace_generic_delete_lease(inode, fl);
1682 if (fl)
1683 error = fl->fl_lmops->lm_change(before, F_UNLCK);
1684 return error;
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001685}
1686
Linus Torvalds1da177e2005-04-16 15:20:36 -07001687/**
1688 * generic_setlease - sets a lease on an open file
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001689 * @filp: file pointer
1690 * @arg: type of lease to obtain
1691 * @flp: input - file_lock to use, output - file_lock inserted
1692 * @priv: private data for lm_setup (may be NULL if lm_setup
1693 * doesn't require it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001694 *
1695 * The (input) flp->fl_lmops->lm_break function is required
1696 * by break_lease().
1697 *
Jeff Layton1c8c6012013-06-21 08:58:15 -04001698 * Called with inode->i_lock held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001699 */
Jeff Laytone6f5c782014-08-22 10:40:25 -04001700int generic_setlease(struct file *filp, long arg, struct file_lock **flp,
1701 void **priv)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001702{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001703 struct dentry *dentry = filp->f_path.dentry;
1704 struct inode *inode = dentry->d_inode;
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001705 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001706
Eric W. Biederman8e96e3b2012-03-03 21:17:15 -08001707 if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE))
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001708 return -EACCES;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001709 if (!S_ISREG(inode->i_mode))
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001710 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001711 error = security_file_lock(filp, arg);
1712 if (error)
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001713 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001714
1715 time_out_leases(inode);
1716
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001717 switch (arg) {
1718 case F_UNLCK:
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001719 return generic_delete_lease(filp);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001720 case F_RDLCK:
1721 case F_WRLCK:
Jeff Layton0efaa7e2014-08-22 10:18:45 -04001722 if (!(*flp)->fl_lmops->lm_break) {
1723 WARN_ON_ONCE(1);
1724 return -ENOLCK;
1725 }
Jeff Laytone6f5c782014-08-22 10:40:25 -04001726 return generic_add_lease(filp, arg, flp, priv);
J. Bruce Fields8335ebd2011-09-21 08:34:32 -04001727 default:
Dave Jones8d657eb2012-07-13 13:35:36 -04001728 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001729 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001730}
Christoph Hellwig0af1a452007-07-31 00:39:22 -07001731EXPORT_SYMBOL(generic_setlease);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001732
Arnd Bergmannb89f4322010-09-18 15:09:31 +02001733/**
Jeff Laytone51673a2014-08-22 18:13:28 -04001734 * vfs_setlease - sets a lease on an open file
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001735 * @filp: file pointer
1736 * @arg: type of lease to obtain
1737 * @lease: file_lock to use when adding a lease
1738 * @priv: private info for lm_setup when adding a lease (may be
1739 * NULL if lm_setup doesn't require it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001740 *
Jeff Laytone51673a2014-08-22 18:13:28 -04001741 * Call this to establish a lease on the file. The "lease" argument is not
1742 * used for F_UNLCK requests and may be NULL. For commands that set or alter
1743 * an existing lease, the (*lease)->fl_lmops->lm_break operation must be set;
1744 * if not, this function will return -ENOLCK (and generate a scary-looking
1745 * stack trace).
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001746 *
1747 * The "priv" pointer is passed directly to the lm_setup function as-is. It
1748 * may be NULL if the lm_setup operation doesn't require it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001749 */
Jeff Laytone6f5c782014-08-22 10:40:25 -04001750int
1751vfs_setlease(struct file *filp, long arg, struct file_lock **lease, void **priv)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001752{
Jeff Layton1c8c6012013-06-21 08:58:15 -04001753 struct inode *inode = file_inode(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001754 int error;
1755
Jeff Layton1c8c6012013-06-21 08:58:15 -04001756 spin_lock(&inode->i_lock);
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001757 if (filp->f_op->setlease)
1758 error = filp->f_op->setlease(filp, arg, lease, priv);
1759 else
1760 error = generic_setlease(filp, arg, lease, priv);
Jeff Layton1c8c6012013-06-21 08:58:15 -04001761 spin_unlock(&inode->i_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001762 return error;
1763}
J. Bruce Fieldsa9933ce2007-06-07 17:09:49 -04001764EXPORT_SYMBOL_GPL(vfs_setlease);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001765
J. Bruce Fields0ceaf6c2010-10-30 17:31:13 -04001766static int do_fcntl_add_lease(unsigned int fd, struct file *filp, long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001767{
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001768 struct file_lock *fl;
Linus Torvaldsf7347ce2010-10-27 12:38:12 -04001769 struct fasync_struct *new;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001770 int error;
1771
Arnd Bergmannc5b1f0d2010-10-27 15:46:08 +02001772 fl = lease_alloc(filp, arg);
1773 if (IS_ERR(fl))
1774 return PTR_ERR(fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001775
Linus Torvaldsf7347ce2010-10-27 12:38:12 -04001776 new = fasync_alloc();
1777 if (!new) {
1778 locks_free_lock(fl);
1779 return -ENOMEM;
1780 }
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001781 new->fa_fd = fd;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001782
Jeff Layton1c7dd2f2014-08-22 10:55:47 -04001783 error = vfs_setlease(filp, arg, &fl, (void **)&new);
Jeff Layton2dfb9282014-08-11 18:14:12 -04001784 if (fl)
1785 locks_free_lock(fl);
Linus Torvaldsf7347ce2010-10-27 12:38:12 -04001786 if (new)
1787 fasync_free(new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001788 return error;
1789}
1790
1791/**
J. Bruce Fields0ceaf6c2010-10-30 17:31:13 -04001792 * fcntl_setlease - sets a lease on an open file
1793 * @fd: open file descriptor
1794 * @filp: file pointer
1795 * @arg: type of lease to obtain
1796 *
1797 * Call this fcntl to establish a lease on the file.
1798 * Note that you also need to call %F_SETSIG to
1799 * receive a signal when the lease is broken.
1800 */
1801int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
1802{
1803 if (arg == F_UNLCK)
Jeff Laytone6f5c782014-08-22 10:40:25 -04001804 return vfs_setlease(filp, F_UNLCK, NULL, NULL);
J. Bruce Fields0ceaf6c2010-10-30 17:31:13 -04001805 return do_fcntl_add_lease(fd, filp, arg);
1806}
1807
1808/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001809 * flock_lock_file_wait - Apply a FLOCK-style lock to a file
1810 * @filp: The file to apply the lock to
1811 * @fl: The lock to be applied
1812 *
1813 * Add a FLOCK style lock to a file.
1814 */
1815int flock_lock_file_wait(struct file *filp, struct file_lock *fl)
1816{
1817 int error;
1818 might_sleep();
1819 for (;;) {
1820 error = flock_lock_file(filp, fl);
Miklos Szeredibde74e42008-07-25 01:48:57 -07001821 if (error != FILE_LOCK_DEFERRED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001822 break;
1823 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
1824 if (!error)
1825 continue;
1826
1827 locks_delete_block(fl);
1828 break;
1829 }
1830 return error;
1831}
1832
1833EXPORT_SYMBOL(flock_lock_file_wait);
1834
1835/**
1836 * sys_flock: - flock() system call.
1837 * @fd: the file descriptor to lock.
1838 * @cmd: the type of lock to apply.
1839 *
1840 * Apply a %FL_FLOCK style lock to an open file descriptor.
1841 * The @cmd can be one of
1842 *
1843 * %LOCK_SH -- a shared lock.
1844 *
1845 * %LOCK_EX -- an exclusive lock.
1846 *
1847 * %LOCK_UN -- remove an existing lock.
1848 *
1849 * %LOCK_MAND -- a `mandatory' flock. This exists to emulate Windows Share Modes.
1850 *
1851 * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
1852 * processes read and write access respectively.
1853 */
Heiko Carstens002c8972009-01-14 14:14:18 +01001854SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001855{
Al Viro2903ff02012-08-28 12:52:22 -04001856 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001857 struct file_lock *lock;
1858 int can_sleep, unlock;
1859 int error;
1860
1861 error = -EBADF;
Al Viro2903ff02012-08-28 12:52:22 -04001862 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001863 goto out;
1864
1865 can_sleep = !(cmd & LOCK_NB);
1866 cmd &= ~LOCK_NB;
1867 unlock = (cmd == LOCK_UN);
1868
Al Viroaeb5d722008-09-02 15:28:45 -04001869 if (!unlock && !(cmd & LOCK_MAND) &&
Al Viro2903ff02012-08-28 12:52:22 -04001870 !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001871 goto out_putf;
1872
Al Viro2903ff02012-08-28 12:52:22 -04001873 error = flock_make_lock(f.file, &lock, cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001874 if (error)
1875 goto out_putf;
1876 if (can_sleep)
1877 lock->fl_flags |= FL_SLEEP;
1878
Al Viro2903ff02012-08-28 12:52:22 -04001879 error = security_file_lock(f.file, lock->fl_type);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001880 if (error)
1881 goto out_free;
1882
Al Viro72c2d532013-09-22 16:27:52 -04001883 if (f.file->f_op->flock)
Al Viro2903ff02012-08-28 12:52:22 -04001884 error = f.file->f_op->flock(f.file,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001885 (can_sleep) ? F_SETLKW : F_SETLK,
1886 lock);
1887 else
Al Viro2903ff02012-08-28 12:52:22 -04001888 error = flock_lock_file_wait(f.file, lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001889
1890 out_free:
Trond Myklebust993dfa82006-03-31 02:30:55 -08001891 locks_free_lock(lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001892
1893 out_putf:
Al Viro2903ff02012-08-28 12:52:22 -04001894 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001895 out:
1896 return error;
1897}
1898
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05001899/**
1900 * vfs_test_lock - test file byte range lock
1901 * @filp: The file to test lock for
J. Bruce Fields6924c552007-05-11 16:22:50 -04001902 * @fl: The lock to test; also used to hold result
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05001903 *
1904 * Returns -ERRNO on failure. Indicates presence of conflicting lock by
1905 * setting conf->fl_type to something other than F_UNLCK.
1906 */
1907int vfs_test_lock(struct file *filp, struct file_lock *fl)
1908{
Al Viro72c2d532013-09-22 16:27:52 -04001909 if (filp->f_op->lock)
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05001910 return filp->f_op->lock(filp, F_GETLK, fl);
1911 posix_test_lock(filp, fl);
1912 return 0;
1913}
1914EXPORT_SYMBOL_GPL(vfs_test_lock);
1915
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05001916static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
1917{
Jeff Laytoncff2fce2014-04-22 08:24:32 -04001918 flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid;
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05001919#if BITS_PER_LONG == 32
1920 /*
1921 * Make sure we can represent the posix lock via
1922 * legacy 32bit flock.
1923 */
1924 if (fl->fl_start > OFFT_OFFSET_MAX)
1925 return -EOVERFLOW;
1926 if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX)
1927 return -EOVERFLOW;
1928#endif
1929 flock->l_start = fl->fl_start;
1930 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
1931 fl->fl_end - fl->fl_start + 1;
1932 flock->l_whence = 0;
J. Bruce Fields129a84d2007-05-10 18:38:43 -04001933 flock->l_type = fl->fl_type;
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05001934 return 0;
1935}
1936
1937#if BITS_PER_LONG == 32
1938static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
1939{
Jeff Laytoncff2fce2014-04-22 08:24:32 -04001940 flock->l_pid = IS_OFDLCK(fl) ? -1 : fl->fl_pid;
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05001941 flock->l_start = fl->fl_start;
1942 flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
1943 fl->fl_end - fl->fl_start + 1;
1944 flock->l_whence = 0;
1945 flock->l_type = fl->fl_type;
1946}
1947#endif
1948
Linus Torvalds1da177e2005-04-16 15:20:36 -07001949/* Report the first existing lock that would conflict with l.
1950 * This implements the F_GETLK command of fcntl().
1951 */
Jeff Laytonc1e62b82014-02-03 12:13:09 -05001952int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock __user *l)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001953{
Marc Eshel9d6a8c52007-02-21 00:55:18 -05001954 struct file_lock file_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001955 struct flock flock;
1956 int error;
1957
1958 error = -EFAULT;
1959 if (copy_from_user(&flock, l, sizeof(flock)))
1960 goto out;
1961 error = -EINVAL;
1962 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
1963 goto out;
1964
1965 error = flock_to_posix_lock(filp, &file_lock, &flock);
1966 if (error)
1967 goto out;
1968
Jeff Layton0d3f7a22014-04-22 08:23:58 -04001969 if (cmd == F_OFD_GETLK) {
Jeff Layton90478932014-03-04 10:30:23 -05001970 error = -EINVAL;
1971 if (flock.l_pid != 0)
1972 goto out;
1973
Jeff Layton5d50ffd2014-02-03 12:13:10 -05001974 cmd = F_GETLK;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04001975 file_lock.fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02001976 file_lock.fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05001977 }
1978
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05001979 error = vfs_test_lock(filp, &file_lock);
1980 if (error)
1981 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001982
Marc Eshel9d6a8c52007-02-21 00:55:18 -05001983 flock.l_type = file_lock.fl_type;
1984 if (file_lock.fl_type != F_UNLCK) {
1985 error = posix_lock_to_flock(&flock, &file_lock);
J. Bruce Fieldsc2fa1b82007-02-20 16:10:11 -05001986 if (error)
Kinglong Meef3282962014-08-22 10:18:43 -04001987 goto rel_priv;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001988 }
1989 error = -EFAULT;
1990 if (!copy_to_user(l, &flock, sizeof(flock)))
1991 error = 0;
Kinglong Meef3282962014-08-22 10:18:43 -04001992rel_priv:
1993 locks_release_private(&file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001994out:
1995 return error;
1996}
1997
Marc Eshel7723ec92007-01-18 15:08:55 -05001998/**
1999 * vfs_lock_file - file byte range lock
2000 * @filp: The file to apply the lock to
2001 * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
2002 * @fl: The lock to be applied
Marc Eshel150b3932007-01-18 16:15:35 -05002003 * @conf: Place to return a copy of the conflicting lock, if found.
2004 *
2005 * A caller that doesn't care about the conflicting lock may pass NULL
2006 * as the final argument.
2007 *
2008 * If the filesystem defines a private ->lock() method, then @conf will
2009 * be left unchanged; so a caller that cares should initialize it to
2010 * some acceptable default.
Marc Eshel2beb6612006-12-05 23:31:28 -05002011 *
2012 * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
2013 * locks, the ->lock() interface may return asynchronously, before the lock has
2014 * been granted or denied by the underlying filesystem, if (and only if)
J. Bruce Fields8fb47a42011-07-20 20:21:59 -04002015 * lm_grant is set. Callers expecting ->lock() to return asynchronously
Marc Eshel2beb6612006-12-05 23:31:28 -05002016 * will only use F_SETLK, not F_SETLKW; they will set FL_SLEEP if (and only if)
2017 * the request is for a blocking lock. When ->lock() does return asynchronously,
J. Bruce Fields8fb47a42011-07-20 20:21:59 -04002018 * it must return FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock
Marc Eshel2beb6612006-12-05 23:31:28 -05002019 * request completes.
2020 * If the request is for non-blocking lock the file system should return
Miklos Szeredibde74e42008-07-25 01:48:57 -07002021 * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
2022 * with the result. If the request timed out the callback routine will return a
Marc Eshel2beb6612006-12-05 23:31:28 -05002023 * nonzero return code and the file system should release the lock. The file
2024 * system is also responsible to keep a corresponding posix lock when it
2025 * grants a lock so the VFS can find out which locks are locally held and do
2026 * the correct lock cleanup when required.
2027 * The underlying filesystem must not drop the kernel lock or call
J. Bruce Fields8fb47a42011-07-20 20:21:59 -04002028 * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED
Marc Eshel2beb6612006-12-05 23:31:28 -05002029 * return code.
Marc Eshel7723ec92007-01-18 15:08:55 -05002030 */
Marc Eshel150b3932007-01-18 16:15:35 -05002031int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf)
Marc Eshel7723ec92007-01-18 15:08:55 -05002032{
Al Viro72c2d532013-09-22 16:27:52 -04002033 if (filp->f_op->lock)
Marc Eshel7723ec92007-01-18 15:08:55 -05002034 return filp->f_op->lock(filp, cmd, fl);
2035 else
Marc Eshel150b3932007-01-18 16:15:35 -05002036 return posix_lock_file(filp, fl, conf);
Marc Eshel7723ec92007-01-18 15:08:55 -05002037}
2038EXPORT_SYMBOL_GPL(vfs_lock_file);
2039
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002040static int do_lock_file_wait(struct file *filp, unsigned int cmd,
2041 struct file_lock *fl)
2042{
2043 int error;
2044
2045 error = security_file_lock(filp, fl->fl_type);
2046 if (error)
2047 return error;
2048
Miklos Szeredi764c76b2008-07-25 01:48:58 -07002049 for (;;) {
2050 error = vfs_lock_file(filp, cmd, fl, NULL);
2051 if (error != FILE_LOCK_DEFERRED)
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002052 break;
Miklos Szeredi764c76b2008-07-25 01:48:58 -07002053 error = wait_event_interruptible(fl->fl_wait, !fl->fl_next);
2054 if (!error)
2055 continue;
2056
2057 locks_delete_block(fl);
2058 break;
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002059 }
2060
2061 return error;
2062}
2063
Jeff Laytoncf01f4e2014-05-09 11:41:54 -04002064/* Ensure that fl->fl_filp has compatible f_mode for F_SETLK calls */
2065static int
2066check_fmode_for_setlk(struct file_lock *fl)
2067{
2068 switch (fl->fl_type) {
2069 case F_RDLCK:
2070 if (!(fl->fl_file->f_mode & FMODE_READ))
2071 return -EBADF;
2072 break;
2073 case F_WRLCK:
2074 if (!(fl->fl_file->f_mode & FMODE_WRITE))
2075 return -EBADF;
2076 }
2077 return 0;
2078}
2079
Linus Torvalds1da177e2005-04-16 15:20:36 -07002080/* Apply the lock described by l to an open file descriptor.
2081 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2082 */
Peter Staubachc2936212005-07-27 11:45:09 -07002083int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
2084 struct flock __user *l)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002085{
2086 struct file_lock *file_lock = locks_alloc_lock();
2087 struct flock flock;
2088 struct inode *inode;
Al Viro0b2bac22008-05-06 13:58:34 -04002089 struct file *f;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002090 int error;
2091
2092 if (file_lock == NULL)
2093 return -ENOLCK;
2094
2095 /*
2096 * This might block, so we do it before checking the inode.
2097 */
2098 error = -EFAULT;
2099 if (copy_from_user(&flock, l, sizeof(flock)))
2100 goto out;
2101
Al Viro496ad9a2013-01-23 17:07:38 -05002102 inode = file_inode(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002103
2104 /* Don't allow mandatory locks on files that may be memory mapped
2105 * and shared.
2106 */
Pavel Emelyanova16877c2007-10-01 14:41:11 -07002107 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002108 error = -EAGAIN;
2109 goto out;
2110 }
2111
Peter Staubachc2936212005-07-27 11:45:09 -07002112again:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002113 error = flock_to_posix_lock(filp, file_lock, &flock);
2114 if (error)
2115 goto out;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002116
Jeff Laytoncf01f4e2014-05-09 11:41:54 -04002117 error = check_fmode_for_setlk(file_lock);
2118 if (error)
2119 goto out;
2120
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002121 /*
2122 * If the cmd is requesting file-private locks, then set the
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002123 * FL_OFDLCK flag and override the owner.
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002124 */
2125 switch (cmd) {
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002126 case F_OFD_SETLK:
Jeff Layton90478932014-03-04 10:30:23 -05002127 error = -EINVAL;
2128 if (flock.l_pid != 0)
2129 goto out;
2130
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002131 cmd = F_SETLK;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002132 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002133 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002134 break;
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002135 case F_OFD_SETLKW:
Jeff Layton90478932014-03-04 10:30:23 -05002136 error = -EINVAL;
2137 if (flock.l_pid != 0)
2138 goto out;
2139
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002140 cmd = F_SETLKW;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002141 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002142 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002143 /* Fallthrough */
2144 case F_SETLKW:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002145 file_lock->fl_flags |= FL_SLEEP;
2146 }
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002147
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002148 error = do_lock_file_wait(filp, cmd, file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002149
Peter Staubachc2936212005-07-27 11:45:09 -07002150 /*
2151 * Attempt to detect a close/fcntl race and recover by
2152 * releasing the lock that was just acquired.
2153 */
Al Viro0b2bac22008-05-06 13:58:34 -04002154 /*
2155 * we need that spin_lock here - it prevents reordering between
2156 * update of inode->i_flock and check for it done in close().
2157 * rcu_read_lock() wouldn't do.
2158 */
2159 spin_lock(&current->files->file_lock);
2160 f = fcheck(fd);
2161 spin_unlock(&current->files->file_lock);
2162 if (!error && f != filp && flock.l_type != F_UNLCK) {
Peter Staubachc2936212005-07-27 11:45:09 -07002163 flock.l_type = F_UNLCK;
2164 goto again;
2165 }
2166
2167out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002168 locks_free_lock(file_lock);
2169 return error;
2170}
2171
2172#if BITS_PER_LONG == 32
2173/* Report the first existing lock that would conflict with l.
2174 * This implements the F_GETLK command of fcntl().
2175 */
Jeff Laytonc1e62b82014-02-03 12:13:09 -05002176int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002177{
Marc Eshel9d6a8c52007-02-21 00:55:18 -05002178 struct file_lock file_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002179 struct flock64 flock;
2180 int error;
2181
2182 error = -EFAULT;
2183 if (copy_from_user(&flock, l, sizeof(flock)))
2184 goto out;
2185 error = -EINVAL;
2186 if ((flock.l_type != F_RDLCK) && (flock.l_type != F_WRLCK))
2187 goto out;
2188
2189 error = flock64_to_posix_lock(filp, &file_lock, &flock);
2190 if (error)
2191 goto out;
2192
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002193 if (cmd == F_OFD_GETLK) {
Jeff Layton90478932014-03-04 10:30:23 -05002194 error = -EINVAL;
2195 if (flock.l_pid != 0)
2196 goto out;
2197
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002198 cmd = F_GETLK64;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002199 file_lock.fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002200 file_lock.fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002201 }
2202
J. Bruce Fields3ee17ab2007-02-21 00:58:50 -05002203 error = vfs_test_lock(filp, &file_lock);
2204 if (error)
2205 goto out;
2206
Marc Eshel9d6a8c52007-02-21 00:55:18 -05002207 flock.l_type = file_lock.fl_type;
2208 if (file_lock.fl_type != F_UNLCK)
2209 posix_lock_to_flock64(&flock, &file_lock);
2210
Linus Torvalds1da177e2005-04-16 15:20:36 -07002211 error = -EFAULT;
2212 if (!copy_to_user(l, &flock, sizeof(flock)))
2213 error = 0;
Kinglong Meef3282962014-08-22 10:18:43 -04002214
2215 locks_release_private(&file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002216out:
2217 return error;
2218}
2219
2220/* Apply the lock described by l to an open file descriptor.
2221 * This implements both the F_SETLK and F_SETLKW commands of fcntl().
2222 */
Peter Staubachc2936212005-07-27 11:45:09 -07002223int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
2224 struct flock64 __user *l)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002225{
2226 struct file_lock *file_lock = locks_alloc_lock();
2227 struct flock64 flock;
2228 struct inode *inode;
Al Viro0b2bac22008-05-06 13:58:34 -04002229 struct file *f;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002230 int error;
2231
2232 if (file_lock == NULL)
2233 return -ENOLCK;
2234
2235 /*
2236 * This might block, so we do it before checking the inode.
2237 */
2238 error = -EFAULT;
2239 if (copy_from_user(&flock, l, sizeof(flock)))
2240 goto out;
2241
Al Viro496ad9a2013-01-23 17:07:38 -05002242 inode = file_inode(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002243
2244 /* Don't allow mandatory locks on files that may be memory mapped
2245 * and shared.
2246 */
Pavel Emelyanova16877c2007-10-01 14:41:11 -07002247 if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002248 error = -EAGAIN;
2249 goto out;
2250 }
2251
Peter Staubachc2936212005-07-27 11:45:09 -07002252again:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002253 error = flock64_to_posix_lock(filp, file_lock, &flock);
2254 if (error)
2255 goto out;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002256
Jeff Laytoncf01f4e2014-05-09 11:41:54 -04002257 error = check_fmode_for_setlk(file_lock);
2258 if (error)
2259 goto out;
2260
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002261 /*
2262 * If the cmd is requesting file-private locks, then set the
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002263 * FL_OFDLCK flag and override the owner.
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002264 */
2265 switch (cmd) {
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002266 case F_OFD_SETLK:
Jeff Layton90478932014-03-04 10:30:23 -05002267 error = -EINVAL;
2268 if (flock.l_pid != 0)
2269 goto out;
2270
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002271 cmd = F_SETLK64;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002272 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002273 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002274 break;
Jeff Layton0d3f7a22014-04-22 08:23:58 -04002275 case F_OFD_SETLKW:
Jeff Layton90478932014-03-04 10:30:23 -05002276 error = -EINVAL;
2277 if (flock.l_pid != 0)
2278 goto out;
2279
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002280 cmd = F_SETLKW64;
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002281 file_lock->fl_flags |= FL_OFDLCK;
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002282 file_lock->fl_owner = filp;
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002283 /* Fallthrough */
2284 case F_SETLKW64:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002285 file_lock->fl_flags |= FL_SLEEP;
2286 }
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002287
Miklos Szeredib648a6d2008-07-25 01:48:57 -07002288 error = do_lock_file_wait(filp, cmd, file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002289
Peter Staubachc2936212005-07-27 11:45:09 -07002290 /*
2291 * Attempt to detect a close/fcntl race and recover by
2292 * releasing the lock that was just acquired.
2293 */
Al Viro0b2bac22008-05-06 13:58:34 -04002294 spin_lock(&current->files->file_lock);
2295 f = fcheck(fd);
2296 spin_unlock(&current->files->file_lock);
2297 if (!error && f != filp && flock.l_type != F_UNLCK) {
Peter Staubachc2936212005-07-27 11:45:09 -07002298 flock.l_type = F_UNLCK;
2299 goto again;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002300 }
2301
2302out:
2303 locks_free_lock(file_lock);
2304 return error;
2305}
2306#endif /* BITS_PER_LONG == 32 */
2307
2308/*
2309 * This function is called when the file is being removed
2310 * from the task's fd array. POSIX locks belonging to this task
2311 * are deleted at this time.
2312 */
2313void locks_remove_posix(struct file *filp, fl_owner_t owner)
2314{
Miklos Szerediff7b86b2006-06-23 02:05:11 -07002315 struct file_lock lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002316
2317 /*
2318 * If there are no locks held on this file, we don't need to call
2319 * posix_lock_file(). Another process could be setting a lock on this
2320 * file at the same time, but we wouldn't remove that lock anyway.
2321 */
Al Viro496ad9a2013-01-23 17:07:38 -05002322 if (!file_inode(filp)->i_flock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002323 return;
2324
2325 lock.fl_type = F_UNLCK;
Miklos Szeredi75e1fcc2006-06-23 02:05:12 -07002326 lock.fl_flags = FL_POSIX | FL_CLOSE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002327 lock.fl_start = 0;
2328 lock.fl_end = OFFSET_MAX;
2329 lock.fl_owner = owner;
2330 lock.fl_pid = current->tgid;
2331 lock.fl_file = filp;
2332 lock.fl_ops = NULL;
2333 lock.fl_lmops = NULL;
2334
Marc Eshel150b3932007-01-18 16:15:35 -05002335 vfs_lock_file(filp, F_SETLK, &lock, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002336
Linus Torvalds1da177e2005-04-16 15:20:36 -07002337 if (lock.fl_ops && lock.fl_ops->fl_release_private)
2338 lock.fl_ops->fl_release_private(&lock);
2339}
2340
2341EXPORT_SYMBOL(locks_remove_posix);
2342
2343/*
2344 * This function is called on the last close of an open file.
2345 */
Jeff Layton78ed8a12014-02-03 12:13:08 -05002346void locks_remove_file(struct file *filp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002347{
Al Viro496ad9a2013-01-23 17:07:38 -05002348 struct inode * inode = file_inode(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002349 struct file_lock *fl;
2350 struct file_lock **before;
Jeff Laytoned9814d2014-08-11 14:20:31 -04002351 LIST_HEAD(dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002352
2353 if (!inode->i_flock)
2354 return;
2355
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002356 locks_remove_posix(filp, filp);
Jeff Layton5d50ffd2014-02-03 12:13:10 -05002357
Al Viro72c2d532013-09-22 16:27:52 -04002358 if (filp->f_op->flock) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002359 struct file_lock fl = {
Christoph Hellwig73a8f5f2014-07-13 17:00:38 +02002360 .fl_owner = filp,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002361 .fl_pid = current->tgid,
2362 .fl_file = filp,
2363 .fl_flags = FL_FLOCK,
2364 .fl_type = F_UNLCK,
2365 .fl_end = OFFSET_MAX,
2366 };
2367 filp->f_op->flock(filp, F_SETLKW, &fl);
Trond Myklebust80fec4c2005-06-22 17:16:31 +00002368 if (fl.fl_ops && fl.fl_ops->fl_release_private)
2369 fl.fl_ops->fl_release_private(&fl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002370 }
2371
Jeff Layton1c8c6012013-06-21 08:58:15 -04002372 spin_lock(&inode->i_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002373 before = &inode->i_flock;
2374
2375 while ((fl = *before) != NULL) {
2376 if (fl->fl_file == filp) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002377 if (IS_LEASE(fl)) {
2378 lease_modify(before, F_UNLCK);
2379 continue;
2380 }
Jeff Layton8c3cac52014-02-03 12:13:07 -05002381
2382 /*
2383 * There's a leftover lock on the list of a type that
2384 * we didn't expect to see. Most likely a classic
2385 * POSIX lock that ended up not getting released
2386 * properly, or that raced onto the list somehow. Log
2387 * some info about it and then just remove it from
2388 * the list.
2389 */
2390 WARN(!IS_FLOCK(fl),
2391 "leftover lock: dev=%u:%u ino=%lu type=%hhd flags=0x%x start=%lld end=%lld\n",
2392 MAJOR(inode->i_sb->s_dev),
2393 MINOR(inode->i_sb->s_dev), inode->i_ino,
2394 fl->fl_type, fl->fl_flags,
2395 fl->fl_start, fl->fl_end);
2396
Jeff Laytoned9814d2014-08-11 14:20:31 -04002397 locks_delete_lock(before, &dispose);
Jeff Layton8c3cac52014-02-03 12:13:07 -05002398 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002399 }
2400 before = &fl->fl_next;
2401 }
Jeff Layton1c8c6012013-06-21 08:58:15 -04002402 spin_unlock(&inode->i_lock);
Jeff Laytoned9814d2014-08-11 14:20:31 -04002403 locks_dispose_list(&dispose);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002404}
2405
2406/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002407 * posix_unblock_lock - stop waiting for a file lock
Linus Torvalds1da177e2005-04-16 15:20:36 -07002408 * @waiter: the lock which was waiting
2409 *
2410 * lockd needs to block waiting for locks.
2411 */
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002412int
Jeff Laytonf891a292013-06-21 08:58:09 -04002413posix_unblock_lock(struct file_lock *waiter)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002414{
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002415 int status = 0;
2416
Jeff Layton7b2296a2013-06-21 08:58:20 -04002417 spin_lock(&blocked_lock_lock);
J. Bruce Fields5996a292006-01-03 09:55:44 +01002418 if (waiter->fl_next)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002419 __locks_delete_block(waiter);
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002420 else
2421 status = -ENOENT;
Jeff Layton7b2296a2013-06-21 08:58:20 -04002422 spin_unlock(&blocked_lock_lock);
J. Bruce Fields64a318e2006-01-03 09:55:46 +01002423 return status;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002424}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002425EXPORT_SYMBOL(posix_unblock_lock);
2426
Marc Eshel9b9d2ab2007-01-18 17:52:58 -05002427/**
2428 * vfs_cancel_lock - file byte range unblock lock
2429 * @filp: The file to apply the unblock to
2430 * @fl: The lock to be unblocked
2431 *
2432 * Used by lock managers to cancel blocked requests
2433 */
2434int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
2435{
Al Viro72c2d532013-09-22 16:27:52 -04002436 if (filp->f_op->lock)
Marc Eshel9b9d2ab2007-01-18 17:52:58 -05002437 return filp->f_op->lock(filp, F_CANCELLK, fl);
2438 return 0;
2439}
2440
2441EXPORT_SYMBOL_GPL(vfs_cancel_lock);
2442
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002443#ifdef CONFIG_PROC_FS
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002444#include <linux/proc_fs.h>
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002445#include <linux/seq_file.h>
2446
Jeff Layton7012b022013-06-21 08:58:22 -04002447struct locks_iterator {
2448 int li_cpu;
2449 loff_t li_pos;
2450};
2451
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002452static void lock_get_status(struct seq_file *f, struct file_lock *fl,
Jerome Marchand99dc8292010-10-26 14:22:33 -07002453 loff_t id, char *pfx)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002454{
2455 struct inode *inode = NULL;
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002456 unsigned int fl_pid;
2457
2458 if (fl->fl_nspid)
Pavel Emelyanov6c5f3e72008-02-08 04:19:20 -08002459 fl_pid = pid_vnr(fl->fl_nspid);
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002460 else
2461 fl_pid = fl->fl_pid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002462
2463 if (fl->fl_file != NULL)
Al Viro496ad9a2013-01-23 17:07:38 -05002464 inode = file_inode(fl->fl_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002465
Jerome Marchand99dc8292010-10-26 14:22:33 -07002466 seq_printf(f, "%lld:%s ", id, pfx);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002467 if (IS_POSIX(fl)) {
Jeff Laytonc918d422014-02-03 12:13:09 -05002468 if (fl->fl_flags & FL_ACCESS)
Fabian Frederick5315c262014-05-09 14:13:05 -04002469 seq_puts(f, "ACCESS");
Jeff Laytoncff2fce2014-04-22 08:24:32 -04002470 else if (IS_OFDLCK(fl))
Fabian Frederick5315c262014-05-09 14:13:05 -04002471 seq_puts(f, "OFDLCK");
Jeff Laytonc918d422014-02-03 12:13:09 -05002472 else
Fabian Frederick5315c262014-05-09 14:13:05 -04002473 seq_puts(f, "POSIX ");
Jeff Laytonc918d422014-02-03 12:13:09 -05002474
2475 seq_printf(f, " %s ",
Linus Torvalds1da177e2005-04-16 15:20:36 -07002476 (inode == NULL) ? "*NOINODE*" :
Pavel Emelyanova16877c2007-10-01 14:41:11 -07002477 mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002478 } else if (IS_FLOCK(fl)) {
2479 if (fl->fl_type & LOCK_MAND) {
Fabian Frederick5315c262014-05-09 14:13:05 -04002480 seq_puts(f, "FLOCK MSNFS ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002481 } else {
Fabian Frederick5315c262014-05-09 14:13:05 -04002482 seq_puts(f, "FLOCK ADVISORY ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002483 }
2484 } else if (IS_LEASE(fl)) {
Jeff Layton8144f1f2014-08-11 13:36:54 -04002485 if (fl->fl_flags & FL_DELEG)
2486 seq_puts(f, "DELEG ");
2487 else
2488 seq_puts(f, "LEASE ");
2489
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -04002490 if (lease_breaking(fl))
Fabian Frederick5315c262014-05-09 14:13:05 -04002491 seq_puts(f, "BREAKING ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002492 else if (fl->fl_file)
Fabian Frederick5315c262014-05-09 14:13:05 -04002493 seq_puts(f, "ACTIVE ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002494 else
Fabian Frederick5315c262014-05-09 14:13:05 -04002495 seq_puts(f, "BREAKER ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002496 } else {
Fabian Frederick5315c262014-05-09 14:13:05 -04002497 seq_puts(f, "UNKNOWN UNKNOWN ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002498 }
2499 if (fl->fl_type & LOCK_MAND) {
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002500 seq_printf(f, "%s ",
Linus Torvalds1da177e2005-04-16 15:20:36 -07002501 (fl->fl_type & LOCK_READ)
2502 ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ "
2503 : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
2504 } else {
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002505 seq_printf(f, "%s ",
J. Bruce Fieldsab83fa42011-07-26 20:10:51 -04002506 (lease_breaking(fl))
Jeff Layton0ee5c6d2012-08-02 15:46:30 -04002507 ? (fl->fl_type == F_UNLCK) ? "UNLCK" : "READ "
2508 : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002509 }
2510 if (inode) {
2511#ifdef WE_CAN_BREAK_LSLK_NOW
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002512 seq_printf(f, "%d %s:%ld ", fl_pid,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002513 inode->i_sb->s_id, inode->i_ino);
2514#else
2515 /* userspace relies on this representation of dev_t ;-( */
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002516 seq_printf(f, "%d %02x:%02x:%ld ", fl_pid,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002517 MAJOR(inode->i_sb->s_dev),
2518 MINOR(inode->i_sb->s_dev), inode->i_ino);
2519#endif
2520 } else {
Vitaliy Gusevab1f1612008-01-17 00:07:08 +00002521 seq_printf(f, "%d <none>:0 ", fl_pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002522 }
2523 if (IS_POSIX(fl)) {
2524 if (fl->fl_end == OFFSET_MAX)
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002525 seq_printf(f, "%Ld EOF\n", fl->fl_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002526 else
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002527 seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002528 } else {
Fabian Frederick5315c262014-05-09 14:13:05 -04002529 seq_puts(f, "0 EOF\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -07002530 }
2531}
2532
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002533static int locks_show(struct seq_file *f, void *v)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002534{
Jeff Layton7012b022013-06-21 08:58:22 -04002535 struct locks_iterator *iter = f->private;
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002536 struct file_lock *fl, *bfl;
2537
Jeff Layton139ca042013-06-21 08:58:17 -04002538 fl = hlist_entry(v, struct file_lock, fl_link);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002539
Jeff Layton7012b022013-06-21 08:58:22 -04002540 lock_get_status(f, fl, iter->li_pos, "");
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002541
2542 list_for_each_entry(bfl, &fl->fl_block, fl_block)
Jeff Layton7012b022013-06-21 08:58:22 -04002543 lock_get_status(f, bfl, iter->li_pos, " ->");
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002544
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002545 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002546}
2547
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002548static void *locks_start(struct seq_file *f, loff_t *pos)
Jeff Laytonb03dfdec2014-02-03 12:13:07 -05002549 __acquires(&blocked_lock_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002550{
Jeff Layton7012b022013-06-21 08:58:22 -04002551 struct locks_iterator *iter = f->private;
Jerome Marchand99dc8292010-10-26 14:22:33 -07002552
Jeff Layton7012b022013-06-21 08:58:22 -04002553 iter->li_pos = *pos + 1;
2554 lg_global_lock(&file_lock_lglock);
Jeff Layton7b2296a2013-06-21 08:58:20 -04002555 spin_lock(&blocked_lock_lock);
Jeff Layton7012b022013-06-21 08:58:22 -04002556 return seq_hlist_start_percpu(&file_lock_list, &iter->li_cpu, *pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002557}
2558
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002559static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
2560{
Jeff Layton7012b022013-06-21 08:58:22 -04002561 struct locks_iterator *iter = f->private;
2562
2563 ++iter->li_pos;
2564 return seq_hlist_next_percpu(v, &file_lock_list, &iter->li_cpu, pos);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002565}
2566
2567static void locks_stop(struct seq_file *f, void *v)
Jeff Laytonb03dfdec2014-02-03 12:13:07 -05002568 __releases(&blocked_lock_lock)
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002569{
Jeff Layton7b2296a2013-06-21 08:58:20 -04002570 spin_unlock(&blocked_lock_lock);
Jeff Layton7012b022013-06-21 08:58:22 -04002571 lg_global_unlock(&file_lock_lglock);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002572}
2573
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002574static const struct seq_operations locks_seq_operations = {
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002575 .start = locks_start,
2576 .next = locks_next,
2577 .stop = locks_stop,
2578 .show = locks_show,
2579};
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002580
2581static int locks_open(struct inode *inode, struct file *filp)
2582{
Jeff Layton7012b022013-06-21 08:58:22 -04002583 return seq_open_private(filp, &locks_seq_operations,
2584 sizeof(struct locks_iterator));
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002585}
2586
2587static const struct file_operations proc_locks_operations = {
2588 .open = locks_open,
2589 .read = seq_read,
2590 .llseek = seq_lseek,
Jerome Marchand99dc8292010-10-26 14:22:33 -07002591 .release = seq_release_private,
Alexey Dobriyand8ba7a32008-10-04 22:34:18 +04002592};
2593
2594static int __init proc_locks_init(void)
2595{
2596 proc_create("locks", 0, NULL, &proc_locks_operations);
2597 return 0;
2598}
2599module_init(proc_locks_init);
Pavel Emelyanov7f8ada92007-10-01 14:41:15 -07002600#endif
2601
Linus Torvalds1da177e2005-04-16 15:20:36 -07002602static int __init filelock_init(void)
2603{
Jeff Layton7012b022013-06-21 08:58:22 -04002604 int i;
2605
Linus Torvalds1da177e2005-04-16 15:20:36 -07002606 filelock_cache = kmem_cache_create("file_lock_cache",
Miklos Szerediee19cc42011-07-07 13:06:09 +02002607 sizeof(struct file_lock), 0, SLAB_PANIC, NULL);
2608
Jeff Layton7012b022013-06-21 08:58:22 -04002609 lg_lock_init(&file_lock_lglock, "file_lock_lglock");
2610
2611 for_each_possible_cpu(i)
2612 INIT_HLIST_HEAD(per_cpu_ptr(&file_lock_list, i));
2613
Linus Torvalds1da177e2005-04-16 15:20:36 -07002614 return 0;
2615}
2616
2617core_initcall(filelock_init);